Unit 3: Scientific Measurement · Unit 3: Scientific Measurement (Chapter 3) 2 Chemistry Math...

1

Unit 3:

Scientific Measurement (Chapter 3)

2

Chemistry Math Review

The following items should help you recall mathematical ideas important to chemistry. If any of these topics are foreign to you, it is your responsibility to seek out your instructor for extra help. 1. Averages To calculate an average, add all of the data, then divide by the number of data items. EX: Four pennies are weighed in the lab and found to have masses of 2.3 g, 2.5 g, 2.6 g, and 2.3 g. What is the average mass of a penny? Answer: 2.4 g 2. Working with exponents

Addition/Subtraction: The coefficients can be added or subtracted as long as they have the same exponent. EX: A mole of lead atoms weighs 2.32 x 102 grams, A mole of oxygen atoms weighs 1.6 x 101 grams.

What is the total mass of the lead and oxygen atoms? Answer: 2.48 x 102 g

Multiplication/Division: Multiply or divide the coefficients. Then add the exponents if finding a product; subtract the exponents if finding a quotient.

EX: A mole of lead atoms weighs 2.32 x 102 grams and occupies a volume of 2.05 x 101 mL. What is the density of lead (Density = mass/volume) Answer: 1.13 x 101 g/mL or 11.3 g/mL 3. Working with fractions

Addition/Subtraction: Each fraction must have the same denominator, so find the least common denominator. Then simply add the numerators.

EX: 1/2 gallon of acid is added to 3/4 gallon of water. How much diluted acid is produced? Answer: 5/4 or 1 1/4 gallons of acid Multiplication/Division: No LCD is necessary. Simply multiply the numerators and denominators. EX: A box has the following dimensions: 3/4 m, 1/2 m, 5/8 m. What is the volume of the box? Answer: 15/ 64 m3

4. Percentages Percent = (part/whole) x 100 EX: A mole of iron II oxide weighs 159.6 g. The iron in the compound weighs 111.6 g. What percentage of the compound is iron? Answer: 69.92 % 5. Solving for unknowns Often a single variable is solved for in an equation EX: A large egg is weighed in the lab and found to have a total mass (m) of 57 grams. If the density

(D) of an egg is 1.1 g.cm3, what is the volume of the egg? (D = m/V) Answer: 52 cm3

3

Measurement Intro

What’s the difference?

far 5000 km small 32 inches

regular 16 ounces hot 100

0 C

cold 0 0 C

150 150 mL

Measurement - __________________________________________

__________________________________________________________

~ ____________________________________________________ Examples:


10 mL 10 experiments 3 miles 3 apples 8 grams 8 molecules

Exact Numbers - _________________________________________

We assume that ALL __________________________ factors are exact numbers:

1 in = __________________ • 1 m = ___________________

24 hrs = __________________ • 1 km = ___________________

4

Qualitative vs. Quantitative


gets hot how hot? gas produced how much? ppt. formed how much?

gets cold how cold?

Qualitative - _________________________________________

Quantitative - _________________________________________ Qualitative or Quantitative? 1. When you don’t feel well in the morning, what is the first thing your mother usually does?

a. feels your forehead _________________________________

b. takes your temperature _________________________________

2. My car just doesn’t feel right.

a. tire looks flat _________________________________

b. read the pressure _________________________________

5

Numbers Large and Small Scientific Notation

Scientific notation is a method of expressing very large and small numbers in a convenient form:

M x 10 n

This is done by moving the decimal place in the original number so that “M” has a value equal to or greater than one and less than ten. The power “n” is simply the number of places the decimal point has been moved. If the original number is less than one, the exponent is negative; if the original number is greater than one, the exponent is positive. One final note, the number of significant figures must remain the same. Examples: 30500 = ____________________ 9.86 x 10-3 = _____________________

0.0030500 = _____________________ 4.62 x 105 = _____________________

0.0632 = _____________________ 405 x 104 =_____________________

Some rules to follow when operating with exponents: 1) For multiplication a) the “M” values are multiplied b) the powers of ten are added c) the result must be checked for proper scientific notation. 2) For division a) the “M” values are divided b) the powers of subtracted (numerator - denominator) c) the result must be checked for proper scientific notation. To enter numbers in scientific notation on a calculator, perform the following steps: 1) enter the value of "M" For example 1x103, M = _________

2) press "EXP" or "EE" This enters the _________________

3) enter the value of "n" In this case, n = ________________

4) press "=" The answer should be 1000.

Now try typing in 5.070 X 10-2. Write your answer on the line, making sure to keep the correct

number of significant figures. __________________

6

1. Convert the following measurements from ordinary notation to scientific notation. Ordinary Notation Scientific Notation mean wavelength of sodium light

0.0000005893 meters

speed of light in a vacuum

299793000 meters/second

half-life of uranium-235

710000000 years

atomic mass unit

0.000000000000000000000001660531 grams

Avogadro’s number

602300000000000000000000

melting point of tungsten

3410 °C

2. Convert the following measurements from scientific notation to ordinary notation.

Scientific Notation Ordinary Notation mass of an electron

9.109 x 10 -31

kg

charge of a proton

1.6 x 10-19

coulomb

lowest possible temperature

-2.73 x 102 0C

diameter of the Andromeda Galaxy

1.9 x 1019 km

Radius of a hydrogen energy level

5.3 x 10-11

m

3. Perform the following operations. Express your answers in scientific notation.

a. (8.4 x 10-3)

= e. (1.57 x 102)(8.7 x 10-7) =

(2.1 x 102) b. (4.5 x 10

-2)

= f. 11050

(9 x 10-5

) — 2205

c. 980000 g. (3.4 x 10-5

)(7.2 x 10-8

) =

+ 13000

d. (6.9 x 1023

) = h. 0.0240

(1.7 x 1035

) + 0.0097

7

Accuracy vs. Precision

Accuracy – Precision -

**Assume the actual value is the bull’s eye**

NEITHER PRECISE NOR ACCURATE PRECISE, NOT ACCURATE The darts are not clustered together The darts are clustered

and are not near the bull’s eye. together but did not hit the

intended mark.

ACCURATE, NOT PRECISE PRECISE AND ACCURATE

The darts are not clustered, but their The darts are tightly clustered

“average” position is the center of the and their average position is

bull’s eye. the center of the bull’s eye.

8

Determining Error Example: You measure the boiling point of pure water at STP and read the thermometer to be 99.10C. The measurement obtained from the laboratory and from a measuring device is called the

_________________________________ value. You know that the ________________________ value

for the boiling point of water is _______________ 0C.

What is the difference between the actual value and the experimental value? _______________

Percent Error

We often calculate the percent error b/c we are interested in the ___________________________

error, not the _______________________ of error. We want to know the amount by which the

__________________________________ value differs from the ___________________________________

value.

Example: Compare the magnitude & relative, or percent error in the following test scores. 4/5 99/100

Magnitude of error ___________________ ___________________ Percent error ___________________ ___________________ (relative error)

Even though they have the same magnitude of error, which one is actually better?

Example: calculate the % error from the water example above

Percent error =

9

Right on Target

1. What term is used to indicate the degree of agreement that a measurement a. has with the “true value”?____________________________________________________________ b. has with others? ___________________________________________________________________

2. Describe the accuracy and precision of these basketball free-throw shooters. a. 99 out of 100 shots go in the basket. _____________________________________________________ b. 99 out of 100 shots hit the rim and bounce off. ___________________________________________ c. 33 out of 100 shots are made; the rest miss. ______________________________________________

3. Three students made multiple weighings of a copper cylinder, each using a different balance. The correct mass of the cylinder had been previously determined to be 4.44 g. Describe the accuracy and precision of each student’s measurements.

I. Ron Rusts Molly B. Denim Nick L. Meddle Trial 1 4.42 g 4.44 g 4.93 g Trial 2 4.54 g 4.43 g 4.95 g Trial 3 4.68 g 4.45 g 4.94 g Trial 4 4.75 g 4.45 g 4.94 g

I. Ron Rusts: ____________________________________________________________________________

Molly B. Denim: _________________________________________________________________________ Nick L. Meddle: __________________________________________________________________________

4. Calculate the percent error in Nick’s data. Use the average of his results.

5. One way to determine the accuracy of a car’s speedometer is to time how long it takes to travel one mile at 60 mph. If the stop watch reads 62 seconds as the driver passes the mile marker, what is the percent error in the speedometer’s reading?

11

Reading Graduated Equipment

Calibration – _________________________________________________________________________ _____________________________________________________________________________________

Uncertainty – __________________________________________________________________________ ______________________________________________________________________________________

A characteristic of liquids in glass containers is that they curve at the edges. This curvature is called the meniscus. You measure the level at the horizontal center or inside part of the meniscus. With water in glass, the meniscus will curve up at the edges and down in the center so you should read the bottom of the meniscus. Your eye should be level with the top of the liquid and you should read the bottom of the meniscus.

GOLDEN RULE OF MEASURING

12

DIRECTIONS: Determine the calibration and estimated column of the following graduated cylinders. Then read the instruments and place the answer in the space provided. Calibration = ______________ Calibration = ______________ Calibration = ______________ Estimation = ______________ Estimation = ______________ Estimation = ______________ Volume = ________________ Volume = ________________ Volume = ________________ DIRECTIONS: Draw a line in the graduated cylinders below to show the given measurement. __________________ __________________ __________________ DIRECTIONS: Read the length indicated on the metric rulers and place the answer in the space provided. _________________________ _________________________

25 mL

35 mL 5 mL

4 mL

500 mL

400 mL

0 mL

1 mL

0.45 mL

20 mL

30 mL

22.2 mL 340 mL

300 mL

400 mL

0 1 10

cm cm

20

13

Reading Instruments

When reading an instrument, first determine its calibration by looking at the markings. Then estimate the measurement one decimal place to the right of the calibration. For example, if an

instrument is divided into tenths, the measurement must be reported to the hundredths. Determine the calibration and estimated column of the following graduated cylinders. Then read the instruments and place the answer in the space provided.

Cal = __________ Cal = ______________ Cal = ______________ Cal = ______________ Est = __________ Est = ______________ Est = _____________ Est = ______________

________________ ________________ ________________ ________________ Draw a line in the graduated cylinders below to show the given measurement.

________________ ________________ ________________ ________________ Read the length indicated on the metric rulers and place the answer in the space provided.

________________ ________________ ________________ ________________

7 mL

8 mL

30 mL

40 mL

200 mL

300 mL

0.7 mL

0.8 mL

800 mL

900 mL

0 mL

1 mL

40 mL

50 mL

400 mL

500 mL

834 mL 0.3 mL 47.5 mL 460 mL

cm cm cm cm

0 1 30 40 6 7 10 20

14

Counting Significant Figures

EXAMPLES:

345.0 g --> ____ SF 305 g --> ____ SF

0.002 g --> ____ SF 350 g --> ____ SF

0.020 g --> ____ SF 30500 g --> ____ SF

How many significant figures (SF) are in each of the following measurements?

_______ 1) 0.002 _______ 11) 0.800000

_______ 2) 500 _______ 12) 3.003

_______ 3) 170 000 _______ 13) 1 590

_______ 4) 170 000. _______ 14) 1 20 000 000 000.

_______ 5) 0.0030000 _______ 15) 0.00300300

_______ 6) 0.20 _______ 16) 1 005

_______ 7) 0.00055067 _______ 17) 3 000 060

_______ 8) 0.00040004 _______ 18) 0.000006

_______ 9) 0.0101010 _______ 19) 120 000 000 000

_______ 10) 0.004 _______ 20) 66.69000

If a decimal is Present,

start at the Pacific

and draw a line

until you hit the

first non-zero digit.

Everything NOT crossed off is a

significant figure.

If a decimal is Absent,

start at the Atlantic

and draw a line

until you hit the

first non-zero digit.

Everything NOT crossed off is a

significant figure.

15

Rounding Measurements

If the digit immediately to the right of the

last significant figure you want to retain is: Then the last significant figure:

1. greater than or equal to 5 1. is increased by 1.

ex: round 47.68 g to 3 s.f.; 2 s.f.; 1 s.f. ______________ _______________ _____________

ex: round 1.855 mL to 3 s.f.; 2 s.f.; 1 s.f. ______________ _______________ _____________

2. less than 5 2. stays the same.

ex: round 113.2 m to 3 s.f.; 2 s.f.; 1 s.f. ______________ _______________ _____________

ex: round 0.0141 kg to 3 s.f.; 2 s.f.; 1 s.f. ______________ _______________ _____________

**When rounding, be careful not to change the magnitude of the number.

ex: round 1902 sec to 3 s.f.; 2 s.f.; 1 s.f. ______________ _______________ _____________

Round off the following measurements to three significant figures. _________________ 1) 4.9680 cm _________________ 6) 95.969 lb/ft3

_________________ 2) 0.050102 g _________________ 7) 0.00040004 L

_________________ 3) 2..535 mL _________________ 8) 100.00 m

_________________ 4) 40.258 km _________________ 9) 4999.55 mol

_________________ 5) 30216 m/sec _________________ 10) 0.0140 J

Round off the following measurements to the indicated number of SF’s. _________________ 1) 16.8 cm to 1 s.f. _________________ 6) 11.2 lb/ft3 to 1 s.f.

_________________ 2) 7.95 g to 2 s.f. _________________ 7) 100. L to 1 s.f.

_________________ 3) 482.6 mL to 2 s.f. _________________ 8) 5.555 m to 3 s.f.

_________________ 4) 0.0320 km to 3 s.f _________________ 9) 592 mol to 2 s.f.

_________________ 5) 0.0550 m to 2 s.f _________________ 10) 0.0205 sec to 2 s.f.

16

Looking for the Perfect Figure

1. Exact numbers are those numbers considered significant to infinity. Definitions contain exact numbers. For example, in the definition of a foot — 1 ft = 12 in — both the 1 and 12 are considered to be exact, or significant to infinity. If a number is an actual count of something, it is also considered to be exact, such as ,“There are 18 lights in this room.” When an exact number is used in a calculation, it is not considered when determining how many significant figures can be in the answer. Determine whether the following numbers are exact numbers (E) or measurements (M).

a. The elevation of the Mile High City, Denver, Colorado, is 5280 ft. ____________

b. There are 12 eggs in one dozen. ____________

c. The announced attendance at the first Steelers football game was 59,843. ____________

d. The average snowfall in Pittsburgh is 43.5 inches. ____________

e. According to 50states.com, the area of Pennsylvania is 46058 mi2. ____________

f. One inch is defined in the metric system as exactly 2.54 centimeters. ____________

2. Determine the number of significant figures in the following measurements.

a. 6.751 g ________ f. 54.52 cm3 ________ k. 0.157 kg ________

b. 0.016 cm ________ g. 0.12900 mol ________ l. 1.03 x 10-2 km2 ________

c. 0.0067 g ________ h. 0.0230 mL ________ m. 2.690 kg ________

d. 0.070 s ________ i. 26.02 x 1023 atoms ________ n. 2,000,000 cm ________

e. 30.07 g ________ j. 0.157 kg ________ o. 2500 J ________

3. Round off the following measurements to three significant figures.

a. 4.9860 L _____________ e. 2.345 J/s _____________ i. 1.00532 cm3 _____________

b. 95.069 cm _____________ f. 5.5555 mol _____________ j. 0.0610 mL _____________

c. 2.3581 x 103 ___________ g. 400.00 s _____________ k. 0.04158 mol _____________

d. 4.1230 mg _____________ h. 0.000682 g _____________ l. 6000. kg _____________

4. In analyzing a sample of polluted water, a chemist measured out a 25.00 mL water sample with

a pipet. At another point in the analysis, the chemist used a graduated cylinder to measure 25

mL of the solution. What is the difference between 25.00 mL and 25 mL?

____________________________________________________________________________________

____________________________________________________________________________________

____________________________________________________________________________________

17

Calculating with Measurements

COUNT RULE: _________________________________________________________________________________ _______________________________________________________________________________________

1. 1.375 x 102 g 5.0 mL

2. 10.000 mi 2.000 hr

3. 98.0 N x 1.22 m =

4. 21g ÷ 8 mL =

5. (7.32 x 104 dm)(4.1 x 10-10 dm) =

6. (9.051 x 10-2

cal)÷(4.80 x 10-5

g) =

=

=

18

Perform the indicated mathematical operations and round off to the appropriate number of significant figures. Label your answer with the correct unit.

1. The perimeter of this room which measures 31 feet by 28 feet. (P = 2l + 2w)

2. The volume of the room from #2, which is 10 feet high. (V = l x w x h )

3. The density of Au (gold) is 969.8 g occupies a volume of 50.2 mL. (D = m/V)

4. The average weight of three people who weigh 121 lb, 168 lb, and 192 lb.

5. The speed of an electron that circles an atom with a circumference of 6.28 x 10-10 m in 2.0 x 10-17 s. (speed = d/t)

19

Name _________________________________________________________ Period ___________ Scientific Notation Tutorial

Scientific notation is a system for representing a number as a number between _____and ____ multiplied by a power of ___________. It is most useful for presenting very ______________ or very _______________

numbers in a form that is _________________ to use. For example, the following sets of numbers below are

equivalent. However, the numbers on the ___________ can be read much more easily.

253,000,000,000,000,000,000 = ____________________________________

0.0000000000000000000253 = ____________________________________

In scientific notation, numbers are expressed as a number between _______ and ________ multiplied by 10

and raised to an _____________________________.

120.3 = 1.203 x 10____ 100 is the same as 10_____

1203 = 1.203 x 10____ ________ is the same as 103

0.1203 = 1.203 x 10____ 1/10 is the same as 10_____

An easy way to determine the __________________ of ten is to count the _____________________

_____________________ you move.

0.000001203 = _________________________, the decimal place has moved backward

________ positions.

1203000000 = __________________________, the decimal place has moved ______________

9 positions.

Questions: 1. 74,390,000 = _________________________ 2. 0.000009998 = ___________________

3. - 0.0000623 = _________________________ 4. 5.466 x 106 = ___________________

5. 2.3 x 10-4 = _________________________

Concept question: How would express numbers such as 1.5 and 0.2 in scientific notation? _________________

_________________________________________________________________________________________________

Science Connections: The relative strength of an ______________ is expressed as an acid ___________________

constant, such as 3.5 x 10-4 for hydrofluoric acid and _____________________ for hypoiodous acid. Why are

these values usually listed in scientific notation? _______________________________________________________

_________________________________________________________________________________________________

Significant Figure Tutorial Significant figures are a way to communicate the _____________________ of a value. When performing

calculations, keeping track of significant figures is important. A calculated value cannot have _____________

significant figures than the values from which it was derived. Determining the significant digits in a number is

an important concept in scientific _________________________ and _________________________

Any non-zero digit is ______________________.

Any zero to the _________ of a non-zero digit is ________ significant.

Any zero between significant digits is ________________________.

Zeros at the _________________ of a number and to the __________ of the decimal point are

significant.

Zeros at the end of a number _________________ a decimal point are not significant.

20

Example: Determine the number of significant digits in the following numbers (you can also use the

Atlantic/Pacific Rule that you learned in class):

52 _____ • 5.03 _____ •5.20 _____ •0.2000 _____ • 0.0020 _____

52000 _____ •52000.0 _____ •7.45 _____ •745000 _____ • 4.7090 _____

Addition/Subtraction:

When performing a calculation involving addition and subtraction, the decimal ______________ of the

____________ significant digit is the weakest link and it determines the significant figures in the final answer.

After reading example 1, which column contains the last significant figure? (tens/hundreds) circle one

After reading example 2, which column contains the last significant figure? (hundredths/thousandths)

Multiplication/Division:

In a calculation involving multiplication or division, the significant figures of the answer are determined by the

number with the ___________________ significant figures (the weakest link). After reading the example,

explain why the final answer 1.65 only has three significant figures. _____________________________________

_________________________________________________________________________________________________

_________________________________________________________________________________________________

**For addition and subtraction, we are concerned with the _________________ _________________

of the significant figures, while for multiplication and division we are concerned with the

_______________________ of significant figures.**

Sig Figs and Scientific Notation

It is easy to determine the number of significant figures when a number is in scientific notation. Simply

determine the number of significant figures on the number before the _______________________ sign. How

many significant figures are contained in the following numbers?

1.203 x 101 _______ • 4.0 x 103 _______ • 2.05 x 10-4 _______ • 2 x 105 _______

Questions: For #1-3, underline the digits that are significant. For #4-6, show your work for full credit.

1. 507, 320 _____________ 4. 5.16 + 5.9 =

2. 0.00507320 _____________ 5. 10 X 5280 =

3. 5.07320 = _____________ 6. 6.10 + 4.0455 =

0.32000

Concept question: How can we express a number like 2,000,000 meters to show that is has exactly 3 significant

figures? _____________________________________________________________________________________

Science Connections: Scientific researchers depend on significant figures when trying to replicate somebody

else’s experiments and ascertain the amount of care necessary in a given step. How is an experimental

protocol that calls for 5g of potassium different from a method requiring 5.050 g of zinc sulfate? What type of

equipment would be required for each one? _________________________________________________________

_________________________________________________________________________________________________

_________________________________________________________________________________________________

_________________________________________________________________________________________________

21

Unit 3 ~ Problem Set #1

Read pg. 68-76. Pg 70-71 #5-8; pg. 72 #12-14

5. Perform each operation. Express your answers to the correct number of significant figures. a. 61.2 m + 9.35 m + 8.6 m ______________________________

b. 9.44 m – 2.11 m ______________________________

c. 1.36 m + 10.17 m ______________________________

a. 34.61 m – 17.3 m ______________________________

6. Find the total mass of three diamonds that have masses of 14.2 grams, 8.73 grams, and 0.912 gram.

______________________________ 7. Solve each problem. Give your answers to the correct number of significant figures AND in

scientific notation. a. 8.3 meters x 2.22 meters ______________________________

b. 8432 meters ÷ 12.5 ______________________________

8. Calculate the volume of a warehouse that has inside dimensions of 22.4 metes by 11.3 meters by 5.2 meters. (Volume = l x w x h)

______________________________ 12. How does the precision of a calculated answer compare to the precision of the measurements used

to obtain it? ____________________________________________________________________

________________________________________________________________________________

13. A technician experimentally determined the boiling point of octane to be 124.1 0C. The actual boiling point of octane is 125.7 0C. Calculate the error and the percent error.

14. Determine the number of significant figures in each of the following.

a. 11 soccer players __________ b. 0.070020 meter __________ c. 10, 800 meters __________ d. 5.00 cubic meters __________

23

Rocket Scientists’ metric conversion

error doomed Mars orbiter

Investigators say simple math error doomed Mars flight

by Andrew Pollack The New York Times

October 1, 1999 LOS ANGELES– Scientists lost a $125 million spacecraft as it approached Mars last week essentially because they confused feet and pounds with meters and kilograms, NASA said yesterday. An internal review team at NASA’s Jet Propulsion Laboratory, in a preliminary conclusion said engineers at Lockheed Martin Corp., which had built the spacecraft, specified certain measurements about the spacecraft’s thrust in poundals, an English unit, but that NASA scientists thought the information was a metric measurement known as newtons. The resulting miscalculation, undetected for months as the craft was designed, built and launched, meant the Mars Climate Orbiter, as it was called, was off course by about 60 miles as it approached Mars. “This is going to be the cautionary tale that is going to be embedded into introductions to the metric system in elementary school and high school and college physics till the end of time,” said John Pike, director of space policy at the Federation of American Scientists in Washington.

Lockheed’s reaction was equally blunt. “The reaction is disbelief,” said Noel Hinners, vice president for flight systems at Lockheed Martin Astronautics in Denver. “It can’t be something that simple that could cause this to happen.” The finding was a major embarrassment for NASA, which said it was investigating how such a basic error could have gone through the space mission’s checks and balances. “The real issue is not that the data was wrong,” said Edward C. Stone, the director of Jet Propulsion Laboratory in Pasadena, Calif, which was in charge of the mission. “The real issue is that our process did not realize there was this discrepancy and correct for it.” Some experts also wondered how something so basic could have gone undetected for so long. “This is kind of the very first thing in Physics 101 or Engineering 101,” Pike said. “This is the only significant program failure that anyone’s ever heard of that’s due to this.”

24

Metric Proficiency Quiz

1. This line _____ is approximately a. 1 centimeter c. 1 meter

b. 1 decimeter d. 1 millimeter

2. The metric measurement that is slightly larger than a yard is the a. decimeter. c. kilometer. b. meter. d. millimeter.

3. The distance of one kilometer is approximately the same as

a. the width of a school desk. c. the length of the chemistry lab. b. the height of a basketball player. d. the length of an airport runway.

4. The thickness of a dime is approximately

a. ½ centimeter. c. 10 kilometers. b. 1 decimeter. d. 2 millimeters.

5. The normal speed for highway driving is approximately

a. 55 km/hr. c. 90 km/hr. b. 70 km/hr. d. 100 km/hr.

6. Temperature can be measured in

a. Centipede degrees. c. Celsius degrees. b. Seltzer degrees. d. Centimeter degrees.

7. The mass of a pair of tennis shoes is approximately a. 1 gram. c. 100 grams. b. 1 milligram. d. 1 kilogram.

8. The volume of a peanut shell is approximately

a. 2 cubic centimeters. c. 2 liters. b. 50 millimeters. d. 1 cubic decimeter.

9. When the temperature outside is 20

0 C, you should wear

a. a bathing suit. c. a heavy coat. b. light clothing. d. nothing!

10. A kilogram of steak would comfortable feed

a. 1 adult. c. a family of four. b. a chemistry class. d. the NA student body.

11. To measure the distance between two cities, a surveyor would use the

a. centimeter. c. decimeter. b. kilometer. d. meter.

12. The cubic centimeter has about the same volume as

a. a marble. c. the head of a housefly. b. a glass coke bottle. d. a 13’’ TV.

13. Normal body temperature is a. 32

0 C. c. 98.6

0 C.

b. 37 0

C. d. 100 0

C.

14. One teaspoon is equal to a. 5 mL. c. 150 mL. b. 50 mL. d. 250 mL.

15. One inch is about

a. 1.5 mm. c. 50 mm. b. 0.25 m. d. 2.5 cm.

25

The Metric System

The International System of Measurement Measurements consist of both a _________________________ and _____________. They

help scientists ______________________ the mass, length, amount, time, temperature, etc., of a substance.

BUT scientific description should mean the same thing to people all over the world.

There are five fundamental units, or SI units, that we use in this class:

Mass

Length

Amount of a substance

Time

Temperature

The Metric System

prefix Value symbol Algebraic Notation Scientific notation

SM

ALL

SM

ALL

BIG

BIG

26

EXAMPLE: Common Metric Conversions

1 mm = _________________________ m 1 µs = _________________________ s 1Kg = 1000________ 1nm = _________________________ m 1dL = 1 x 10-1 ________ 1pg = _________________________ g 1Mg = _________________________ g 1Gs = _________________________ s

1 mL = _________________________ cm3

The Golden Rule of knowing metric definitions/conversions:

Common ENGLISH CONVERSIONS

ENGLISH - METRIC CONVERSIONS

27

FACTOR LABEL METHOD

A problem-solving method based on treating units in calculations as if they are algebraic factors

Examples:

a. How many days are in 85 years? b. How many seconds are in 100. years? c. How many nanometers are in 1000. meters? d. Convert 250.50 megagrams to micrograms. e. Convert 85 km/hr to cm/s.

29

Unit 3 ~ Problem Set #2 PART I: Read pg. 73 - 76. Complete problems on page 79 #18-24 18. Which five SI base units are commonly used in chemistry?

1. ___________________________ 4. _______________________

2. ___________________________ 5. _______________________

3. ___________________________

19. Which metric units are commonly used to measure:

a. length _________________________ d. temperature _______________________

b. volume ________________________ e. energy _______________________

c. mass ________________________

20. Name the quantity measured by each of the seven SI base units and give the SI symbol of the unit.

(see table 3.1 on page 73)

SI BASE UNITS

Quantity SI Base Unit Symbol

Length

Mass

Temperature

Time

Amount of Substance

Luminous Intensity

Electric Current

21. What is the symbol and meaning of each prefix?

Prefix Symbol Meaning

milli-

deci -

nano -

centi -

22. List the following units in order from largest to smallest: m3, mL, cL, µL, L, dL. __________________

23. What is the volume of a paperback book 21 cm tall, 12 cm wide, and 3.5 cm thick?

24. State the difference between mass and weight. _________________________________________

____________________________________________________________________________________

____________________________________________________________________________________

30

PART II: Read pg. 80 - 86. Complete problems on page 87 #38-45 38. What happens to the numerical value of a measurement that is multiplied by a conversion factor?

What happens to the actual size of the quantity? ________________________________________

____________________________________________________________________________________

39. Why is dimensional analysis (a.k.a. factor label method) useful? ____________________________

____________________________________________________________________________________

40. What types of problems can be solved using dimensional analysis? _________________________

41. What conversion factor would you use to convert between these pairs of units?

a. minutes to hours ________________________ c. dm3 to milliliters _____________________

b. grams to milligrams ______________________

42. Make the following conversions. Express your answers in standard scientific notation.

a. 14.8 g to micrograms

b. 3.72 x 10-3 kg to grams

c. 66.3 L to cubic centimeters (cm3)

43. An atom of gold has a mass of 3.271 x 10-22 g. How many atoms of gold are in 5.00 g of gold?

44. Convert the following. Express your answers in scientific notation.

a. 7.5 x 104 K to kilojoules

b. 3.9 x 105 mg to decigrams

c. 2.21 x 10-4 dL to microliters

45. Light travels at a speed of 3.00 x 1010 cm/s. What is the speed of light in kilometers/hour?

31

x

x

x

x

x

x

x

x

x

Name _________________________________________________________ Period ___________ Dimensional Analysis Tutorial

In order for a numerical value to have _______________________ it must be accompanied by a

_______________, such as ________________, centimeters, or _____________. Very often in calculations, a

quantity needs to be __________________ to another related ______________. This is done using the

_____________ ___________________ method of _______________________ _____________________, which

means changing the units of value by _______________________ by a factor of _____________ (unity).

Real-World Connections:

When units are not properly _____________________, disaster can result. The loss of NASA”s $125 million

_______________ _________________ was the result of not converting from English to metric ____________!

The ________________ _________________ used in dimensional analysis come from true statements, such as

one foot can be divided into ________ inches. The same statement is expressed mathematically as:

1 ft = 12 in

12 in 12 in

1 ft = 12 in

12 in 12 in

1 ft

12 in

Use this unit factor to answer the question, how many feet is 66 inches?

Using the unit factor we just developed, we convert between ____________ and __________.

Canceling the ______________ unit, we are left with units of _________________.

66 in ________

Dimensional analysis can be used to convert between ________________ quantities, and from the metric scale

to the English scale. Using the state 1 inch is _____________ centimeters, we can make any English to metric

length conversion.

5280 ft __________ __________ __________ __________

Using the same unit factors as above, we can convert from kilometers to feet.

1 km __________ __________ __________ __________

Notice the same unit factors are used in the two conversions. The difference is the numerator and

denominator are _____________ depending upon what _____________ we need to ____________. Canceling

the units ensures the conversion is __________________.

Dividing each side of the expression by ______ in produces the

___________ ______________ used in dimensional analysis. This

unit factor is simply a ______________ of one unit type (feet) to

another unit type (inches).

= 1

=

_________

=

_________

=

_________

32

Unit factors do not affect the ____________________ ________________________. Only ____________________

___________________ determine the significant figures.

Properties that involve a ratio can also be used as unit factors. Density, which relates _____________ to

______________, is used as a unit factor in the baseball bat example. When converting cubic feet to cubic

inches, the entire factor must be _________________. We can use mathematical ratios in our dimensional

analysis as well, which comes in handy when dealing with ratios of _________________ and ______________ in

chemical equations.

(note: not every box must be used)

Question 1: Commercial airlines fly at 35,000 feet. How many miles from sea level is this?

35,000 x x x x x = 6.6 mi

Question 2: An Olympic swimming pool is 25 meters long. How long is an Olympic swimming pool in feet?

25 m x x x x x = 82 ft

Question 3: The density of white ash used in making wooden baseball bats is listed as 0.025 lb/in3. The

density of aluminum used in making aluminum baseball bats is 2.70 g/cm3. What is the density of white ash in

g/cm3?

0.025 lb x x x x x = 0.69 g

in3 cm3

Question 4: A can of a certain soda contains 55 milligrams of sodium. If the can of soda is 355 mL, how many

pounds of sodium would there be in one liter of the same soda?

55 mg x x x x x = 0.00034 lb

355 ml L

Question 5: The speed of light is 3.00 x 108 meters per second. What is the speed of light in miles per hour?

3 x 108 m x x x x x = 11,200,000 mi

s hr

Keeping track of ________________ associated with numerical values is imperative in chemistry. Using

dimensional analysis to guide your calculations will greatly reduce common ____________________.

Concept question: You are in a timed competition for drawing a house to scale. Calculators are not allowed in

the competition. Would it be easier to draw your house using metric or English units? Explain your reasoning.

_________________________________________________________________________________________________

_________________________________________________________________________________________________

33

The Metric System

prefix

value symbol

example algebraic notation scientific notation

Giga 1,000,000,000 1 x109 G 6 GL = 6 x 10

9 L

Mega 1,000,000 1 x 106 M 2 Mg = 2 x 10

6 g

kilo 1,000 1 x 103 k 4 kJ = 4 x 10

3 J

deci 0.01 1 x 10-1

d 1 dL = 1 x10-1

L

centi 0.001 1 x 10-2

c 5 cm = 5 x 102 m

milli 0.0001 1 x 10-3

m 7 mg = 7 x 10-3

g

micro 0.000001 1 x 10-6

µ 8 µs = 8 x 10-6

s

nano 0.000000001 1 x 10-9

n 9 nm = 9 x 10-9

m

pico 0.000000000001 1 x 10-12

p 3 pg = 3 x 10-12

g

1. State an equivalent value for the following measurements by eliminating the exponents and adding a

prefix to the SI unit. Ex: the 6 x 106 dollar man = 6 megadollar man a. This class period seems to just fly by, but it actually lasts 2.520 x 103 seconds. ____________________

b. The great pyramid of Cheops is built of 2,300,000 blocks weighing 2.3 x 106 grams each.___________

c. Doc Brown’s time capsule needs 1.21 x 109 watts of power to come “Back to the Future.” __________

d. The Indianapolis 500 race is 8.0 x 105 meters long. ___________________________________________

e. The wavelength of red light used in laser pens is 6.33 x 10—7 m. ________________________________

Perform the following metric conversions:

1. The mass of the moon is approximately 7.36 x 1025 grams. a. What is its mass in gigagrams?

2. The speed on the autobahn section of McKnight Road is 80. km/hr. a. What is the speed in m/hr?

b. Estimate this speed in miles per hour. _____________________________

34

3. Human hair grows at a speed of 0.45 mm/day. a. On average, how many centimeters does hair grow in one year?

b. Estimate this length in inches. _____________________________

4. The radius of the earth is approximately 6.4 gigameters. a. Convert 6.4 Gm to meters.

b. What is the earth’s volume in cubic meters? (The volume of a sphere is 4/3π r3)

c. If seven students can fit into a cubic meter, how many students can cram into the earth?

5. Lake Superior is 4.0 x 104 cm deep at a maximum depth.

a. What is the depth, in km, of the largest Great Lake?

b. Estimate this depth in miles. _______________________________; in feet ________________________

Describe an object that approximates each of the following measurements.

1. 1 decimeter _____________________________________________________

2. 1 gram _____________________________________________________

3. 1 centimeter _____________________________________________________

4. 1 liter _____________________________________________________

5. 1 mL _____________________________________________________

6. 1 kilogram _____________________________________________________

7. 1 meter _____________________________________________________

35

Metric Mayhem DIRECTIONS: use the appropriate metric prefixes and the pictures to solve each puzzle

10-9

10-6

101

10-12

106

36

10-2

10-12

10-1

103

106

37

Measure Your Mind with Metrics Use the factor label method to solve each problem below and record all answers with the correct number of significant figures. For # 5-7, start each conversion with the underlined phrase.

1. Fill in the following blanks. Remember the number, “1” ALWAYS goes with the prefix:

a. 1 µL = ______________ L e. ______ Ms = ______________ s

b. 1 ng = ______________ g f. ______ pm = ______________ m

c. 1 Gm = ______________ m g. ______ cL = ______________ L

d. 1 ds = ______________ s h. ______ Kg = ______________ g

2. Convert the following:

a. 70. µg = __________ mg b. 45 cm3 = __________ L c. 5.6 x 10-7 m = __________ nm

3. A box of spaghetti contains 300 strands of pasta that are 30.48 cm long. How many kilometers of

spaghetti does the box contain? Estimate this length in miles? 4. On average, Roger Federer can serve a tennis ball 120. miles per hour. How fast is this in meters per

second? (HINT: 5280 ft = 1 mile; 2.54 cm = 1 inch)

38

5. Earth is approximately 1.5 x 108 km from the sun. How many minutes does it take light to travel from the sun to Earth? The speed of light is 3.0 x 108 m/s. 6. The mass of a gemstone is often measured in “carats” where 1 carat = 0.200 grams. If the annual

worldwide production of diamonds is 12.5 million carats, how many kilograms does this represent? 7. When I bought my 2003 Jaguar XKE convertible in England, I paid I $0.39/liter for gasoline. To fill up

my Jag, the total cost was $26.86. How many milliliters of gasoline does the tank in my car hold? 8. A technician experimentally determined the boiling point of octane to be 124.10C. The actual boiling

point of octane is 125.70C. Calculate the percent error. 9. a. Read the graduated cylinder. _______________ b. Convert your measurement to megaliters. 10.

a. Read the metric ruler. _______________ b. Convert your measurement to micrometers.

15 mL

5 mL

39

Test Your SI Savvy How many metric know-how do you have? Here’s a chance to find out by testing your understanding of the

International System of Units (SI). Just start with #1 and proceed as directed, writing on the next page, the order in

which you answer the questions. You will get all questions correct eventually. That is the only way to complete the

exercise.

1. The metric system of measurement is based on the meter and the decimal system of ten. If you answer is true, go to 5;

if false, go to 7.

2. How did you get here? This quiz is not 1, 2, 3 order. Return to 1....you get a mulligan!

3. The meter is the basic unit of length. It is longer than a yard. If your answer is true, go to 12; if false, go to 6.

4. Correct! You are very alert. However, much measurement of mass is by the kilogram, which is a little more than two

pounds. Go to 18.

5. You’re right. The metric system, developed by the French, is based on the meter and uses the decimal system to

implement measurements. What could be easier than counting by 10s? Go to question 3.

6. You’re wrong. The base unit of length is the meter which is longer than the yard by a little more than three inches.

Try 3 again.

7. Wrong. The metric system is based on the meter and employs multiples and divisions of 10 to derive its measurement

units. Return to 1 and try again.

8. You’re right! The centimeter is used to measure line segments and replaces the inch measurement. Go to 9.

9. The Latin prefix centi means 1/100 (0.01) of a unit in the metric system, whether it pertains to a length (centimeter),

mass (centigram), or volume (cL). If you answer true, go to 11; if you answer false, go to 17.

10. No. The metric measurement replacing the inch is the centimeter (cm), which is 0.01 of a meter. Try 13 again.

11. Correct. Centimeter, centigram, and centiliter are 0.01 of meter, gram, and liter. Number 15 is next.

12. Super! You remembered that the meter stick replaces the yardstick. And it is 39.37 inches. Go to 13.

13. The unit used to measure line segments is the decimeter, which replaces the inch measurement. If true, go to 10; if

false go to 8.

14. You are lost. Return to your last question.

15. The unit measuring small amounts of mass is the gram. If the answer is true, go to 4; if false, go to 16.

16. Got you! The answer is true. Go back to 15.

17. Oops. You goofed. That statement is true. Adding centi- to meter, gram, or liter indicated 0.01 of that unit. Try 9

again.

18. For you soft drink buffs, this should be easy. Still, be careful. A litter is the most convenient unit of volume. If true go

to 19. If false, go to 22.

19. Really got you this time. Cats and dogs come in litters; liquids are measured in liters! Go back to 18.

20. Correct. There are 1000 mm in one meter. It is also true that is takes 1000 mg to make one gram. Go to 21.

21. A unit of measurement smaller than a meter but 10 times as big as a centimeter is the decimeter. If true, go on to 28;

if false go to 23.

22. Couldn’t pull the wool over your eyes! The liter (not litter) is the unit of volume. A liter is a little more than a quart. Go

to 25.

23. Sorry, the statement is correct. A decimeter is 0.1 of a meter. Go back to 21.

24. Three prefixes smaller than the base units of metric measurement are milli (0.001), deci (0.01), and centi (0.1). If you

agree, go to 32. If you disagree, go to 36.

25. For finer measurement of small items, such as the thickness of a dime, add the prefix milli before the base unit and

measure in millimeters. Since milli means 0.001, 1 mm = 0.001 meters. Does that mean that there are 1000 mm in a

meter? If true, go to 20; if false go to 27.

26. The unit of measurement replacing the mile is the kilometer. If you agree, go to 31; if you disagree, go to 30.

27. It takes 1000 millimeters placed side by side to make one meter. Return to question 25.

40

28. You’re correct. The decimeter (dm), ten times as large as a centimeter, is 0.1 of a meter. It takes 10 dm to equal one

meter. Question 24 is next.

29. Sorry, but you don’t belong here. Please return to your last question.

30. Try again. Pretty soon, we’ll be keeping an eye on how many kilometers per hour we’re cruising down the highway.

Go to 26.

31. Correct. In some states, road signs indicate how many miles and kilometers to the next town. The prefix kilo means

1000. Go on to 37.

32. Try 24 again. Centi means 0.01 and deci means 0.1 of a particular base unit.

33. Oops - wrong. Grams are too small to use conveniently. A nickel weighs about 5 grams. Go back to 37.

34. Right! For example, you will purchase a 3 m by 4 m carpet instead of a 9 ft by 12 ft rug. Go to 38.

35. Wrong. The statement is true. Return to 43.

36. Correct. Deci and centi were transposed. The correct order, as you were able to detect, is centi meaning 0.01 and

deci meaning 0.1. Continue with 26.

37. A kilogram, which is a little more than 2 pounds, is the unit of weight that is used more frequently for everyday

purchases. If this is true, go to 40; if false, go to 33.

38. Milligrams measure large quantities, such as a truckload of elephants. Is this is true, proceed to 39; if false, go to 41.

39. Caught you off guard this time -- you goofed. Milligrams measure small quantities, such as the amount of aspirin in a

Bayer tablet. A metric ton (1000 kg) measures large quantities. Go back to 38.

40. You are right! One gram is not sufficient enough to weigh potatoes. The gram is better for small items such as a

potato chip or M & M. Try 43.

41. You are a pretty smart cookie. Milligrams are small units, 0.001 of a gram. Much larger quantities will be measured in

metric tons (t), which are equivalent to 1000 kg. Try 48 now.

42. Sorry, but the statement is true. The term dekagram is not often used, but the prefix deka means 10 times the base

unit. Try 48 again.

43. In linear measurement, the meter replaces the foot and yard. If the answer is true, go to 34; if false, go to 35.

44. Absolutely correct. The prefix deka attached to meter, liter, or gram means 10 times that unit. Go on to 45.

45. You’re doing fine. Now try this; a race of two hectometers equals 2000 meters. If true, go to 50; if false, go to 54.

46. Negative. This statement is true. Try 49 again.

47. Correct. Go on to 55.

48. Ten grams of paper clips can be called a dekagram. If true, go to 44; if false, proceed to 42.

49. Three prefixes greater than the base unit are kilo, meaning 103, mega, meaning 10

6; and giga, meaning 10

9. If true,

go to 47; if false go to 46.

50. Absolutely, positively wrong. Two thousand meters would be 2 kilometers. Try 45 again.

51. Correct. Body temperature above 370C is feverish; 39

0C, very feverish; and 40

0C is dangerous! Go to 52.

52. A Celsius temperature reading on a very hot summer day would be around 1000C. If true, go to 53; if false, move to

60.

53. Wrong! A temperature reading of 1000C is the boiling point of water; 212

0F

on the Fahrenheit scale. Go back to 52.

54. Good work! You’ve caught on. Hecto added to the unit means 100 times that unit, so a race of 2hm would only be

200 m in distance. Go to 49.

55. A body temperature of 370C is normal and nothing to call the doctor about. If true, go to 51; if false, go to 56.

56. That statement is correct. Try 55 again.

57. Metric symbols are pluralized with the addition of a final “s”. If true, go to 58; if false go to 59.

58. Wrong. Whether used for a single unit or for many units, the symbols remain the same. Try 57 again.

59. Very observant. Metric symbols are never pluralized by adding an “s”. It is 1mm and 75 mm. Also note that a period

is never added after the symbols, unless of course, it is the end of the sentence. Go to 61.

60. Couldn’t fool you! A Celsius reading of 1000C is equivalent to the boiling point of water. A warm day on the Celsius

scale would be 25 - 300C, and a very hot day would be 30 - 40

0C. Try 57.

61. Good job! You made it; you are a true convert!!

41

Name ___________________________________________________________________________ Period __________

DIRECTIONS: Just start with #1 and proceed as directed, writing on the following lines, the order in which you

answer the questions. _______________________________________________________________________________

___________________________________________________________________________________________________

___________________________________________________________________________________________________

DIRECTIONS: Use what you learned during the exercise to answer the following questions about the Metric System. The question where you can find the answer is referenced in parentheses. Please place your answer on the line(s) to the right of the question. 1. A kilogram is a little more than ____ pounds (4). _________________________

2. The ____ is the basic unit of length. (3) _________________________

3. The meter is longer than the yard by a little more than ____ inches. (6) _________________________

4. The metric measurement replacing the inch is the ____ (10) _________________________

5. The centimeter is ____ of a meter. (10) _________________________

6. The ____ stick replaces the yard stick and it is _________ inches. (12) ________________ ______________

7. A ____ is the most convenient way to measure liquids. (19) _________________________

8. There are ____ mm in one meter; 1000 ____ in one gram. (20) ________________ ______________

9. A unit of measurement smaller than a meter but 10 times as big as a centimeter is the ____. (21)

_________________________

10. A liter is a little more than a ____. (22) _________________________

11. What unit of measurement would one use to measure the thickness of a dime? (25) _________________________

12. The unit of measurement replacing the mile is the ____. (26) _________________________

13. The prefix kilo means ____. (31) _________________________

14. A nickel weights about ____ grams. (33) _________________________

15. A metric ton is equal to ____ kilograms. (41) _________________________

16. The prefix deka means ____ times the base unit. (42) _________________________

17. In linear measurement, the ____ replaces the foot and yard. (43) _________________________

18. A race of two hectometers equals ____ meters. (54) _________________________

19. Two thousand meters would be 2 ____ . (50) _________________________

20. Body temperature of ____ is normal. (55); ____ is very feverish. (51) ________________ ______________

21. What is the boiling point of water on the Celsius scale? (53) _________________________

22. Hecto added to a unit means ____ times that unit. (54) _________________________

23. A warm day on the Celsius scale would be ____ - ____. (60) ________________ ______________

24. A very hot day would be ____ - ____. (60) ________________ ______________

43

Name _________________________________________________________ Period ___________

Temperature Conversion Tutorial

Temperature plays an integral role in a number of chemical interactions. Temperature is included in many

equations in this course. The scale on which temperature is measured, however, is dependent upon where

you are in the ________________. In America, we use the ________________________ scale. In most of the rest

of the world, the _________________ scale is used. The __________________ scale is used in many scientific

equations. It becomes important to _______________ between these different scales when studying chemistry.

What is the boiling point of water? Fahrenheit scale ______________ Celsius scale ______________

What is the freezing point of water? Fahrenheit scale ______________ Celsius scale ______________

Neither of these scales is an absolute scale. That means that 0oC and 00F do NOT represent the _____________

point on the scale. Indeed, there are negative temperatures. The Kelvin scale is an ____________________ scale

based on the ______________ degree. ______________ ______________ is the lowest temperature possible.

The Kelvin scale is defined as 0 K is equal to ___________________ oC.

The Celsius degree is ______________ than the Fahrenheit degree.

After reducing the fraction, what is the formula for converting between 0C and 0F? ________________________

Rearrange this formula and solve for 0C. ___________________________________________

What is the formula for converting between 0C and K? __________________________. Rearrange this formula

and solve for 0C. ____________________________________

For equations where temperature is a variable, you must ________________________ what scale is required for

your calculations. Some equations use the Celsius temperature while others use the ________________ scale.

Questions:

1. Convert from the Fahrenheit temperatures shown on the thermometer to the proper Celsius and Kelvin

Temperatures to the nearest whole degree. Show all work for full credit.

Temperature is: __________ 0C __________ K

Work

2. A 2 liter sample of nitrogen gas is held at -600C. What is the temperature of this sample in 0F and K to

the nearest whole degree.?

Temperature is: __________ 0F __________ K

44

Work

3. A scientist mentions his experiments were carried out at 298 K. What temperature is this in 0C and 0F to

the nearest whole degree?

Temperature is: __________ 0C __________ 0F

Work

4. At what temperature will a Celsius thermometer and a Fahrenheit thermometer read the same

temperature?

Temperature is: _________________ degrees

Work

Recognizing the proper temperature ___________ to use for a ______________________ and being able to

convert between the different temperature scales is very important in science.

Science Connections: Both Kelvin and Celsius scales are useful in making ______________________

calculations. The Ideal Gas Law uses the _________________ temperature scale whereas the boiling point

elevation does not require ________________ temperature.

Concept Question: The room in a lab where researchers work with isolated proteins is kept at 40C. How heavy

of clothing do you think they wear? Will a block of ice melt in this room? Explain your reasoning and show all

work for full credit. _______________________________________________________________________________

_________________________________________________________________________________________________

_________________________________________________________________________________________________

_________________________________________________________________________________________________

45

The English system of measurement grew out of the creative

way that people measured for themselves. Familiar objects and parts of the body

were used as measuring devices. For example, people measured shorter distances

on the ground with their feet.

They measured longer distances by their paces (a "mile" was a thousand paces). They measured

capacities with common household items such as cups, pails, and baskets. The word gallon comes from

an old name for a pail.

Unfortunately, these creative measuring devices allowed for different measurements to be obtained

when different people measured the same items. Eventually, a standard was set so that all measurements

represented the same amount for everyone.

The metric system of measurement was created about two hundred years ago by a group

of French scientists to simplify measurement. In the metric system, each of the common kinds of measure

-- length, mass, and capacity -- has one basic unit of measure. The base unit can be scaled up or down

using multiples of ten. The “Metric System” handout from class will help you review the metric prefixes

and the conversion factors that you will need to complete this activity.

46

NAMES ________________________________________________________ PERIOD ______________

DIRECTIONS: You and your lab partner have become great friends through chemistry class, and you have

decided to go on a trip and tour several cities in Europe! As a result of being from the United States, you are

not familiar with using the metric system. However, in Europe, that is their standard system of measurement. In

order to overcome several conversion crossroads and enjoy your trip, you will need to use your English and metric

conversion knowledge. Show all of your work and record all answers with the correct number of significant figures

for full credit!! HINT: Start each conversion with the underlined phrase.

Your flight was delayed out of Pittsburgh and you arrive at the Frankfurt airport at 3:30 pm. After renting a car, you get directions and finally arrive at the hotel at 4:30 pm.You have dinner reservations at a very prominent restaurant for 6:30 pm. This restaurant is very strict and you are not there by the specified time, you will lose your reservation. If it takes 30 minutes to check in and freshen up, will you make it to the restaurant by 6:30? If yes, how many minutes do you have to spare? If not, how late will you be? The restaurant is 1.5 x 105 meters away from the hotel and the speed limit is 112 km/hr (being an inexperienced driver and b/c of the foreign nature of the roads, you NEVER go over the speed limit). Please show all of your work and explain how you arrived at your answer.

Crossroad I: Time is of the Essence

47

You plan to spend the day hiking in Saxony, Switzerland, and will be outside for most of the day. You turn on the weather channel and hear the following report:

“The high temperature for tomorrow will be 24 0C with a chance of rain.

The low temperature will be 10.0C.”

Based on the weather report what are the high and low temperatures in 0F? Show your work. (HINT: Use the temperature conversions you learned from the on-line tutorial)

High: ___________________________________________

Low: ___________________________________________

What should you and your lab partner wear ? ____________________________________________

__________________________________________________________________________________

You decide to send your Chemistry teacher a post card and tell her about the weather. You want to impress her so you report the temperatures in kelvins.

High: ___________________________________________

Low: ___________________________________________

As you travel along a highway you notice kilometer markers and reflectors along the side of the road. There are 21 reflectors between each kilometer marker. If the reflectors are equally spaced, how many feet are between each reflector? Report your answer to 2 significant figures. (HINT: 1 km = 0.625 miles; think about how many spaces are between each reflector—a sketch might help you determine this)

Crossroad II: What Not to Wear

Crossroad III: Traveling Tales

48

You wake up the next morning with a severe headache and decide to take the pain medication that you brought with you from home. It indicates that an adult should take 0.50 fluid ounces per dose. You only have a small measuring cup calibrated in milliliters--how many milliliters should you take for a correct dosage? (HINT: 1 fluid oz = 0.03 L)

You have been invited to a party and the hostess tells you that they are making hamburgers for dinner! She asks you to pick up the ground beef from the local market. How many kilograms of ground beef should you buy to make 120 quarter-pounders? (HINT: 1 lb = 454 g)

As the last adventure, you decide to take a road trip. Your car, which averages 42.6 kilometers per gallon, has a full 65 liter tank of gas for your 1100 kilometer trip. Is this enough gas to complete your trip without refueling? If not, how many liters of gas will you have to buy to complete the trip? (HINT: 1 gallon = 3.78 L)

Crossroad IV: Metric Meds

Crossroad V: BEEF…It’s What’s For Dinner

Crossroad VI: Are We There Yet?

49


Read pg. 73-78. Practice Problems page 78 #16,17; pg. 79 #21,22,25,26 Pg. 78 16. Liquid nitrogen boils at 77.2 K. What is this temperature in degrees Celsius? _________________

17. The element silver melts at 960.8 0C and boils at 2212 0C. Express these temperatures in kelvins.

________________________________________________________________________________

Pg. 79 21. What is the symbol and meaning of each prefix?

a. milli - _____________ b. nano - _____________

c. deci - _____________ d. centi - _____________

22. List the following units in order from largest to smallest: m3, mL, cL, µL, L, dL

_______________________________________________________ 25. State the relationship between degrees Celsius and kelvins.

_________________________________________________________________________________ 26. Surgical instruments may be sterilized by heating at 170 0C for 1.5 hr. Convert 170 0C to kelvins.

_______________

51

Density A B

Box A & B have the same volume Each ball has the same mass

Which box weighs more? ______________

Why? _________________________________________

_______________________________________________

Density = D =

Units of Density:

Liquid = Solids = Gases =

Density is dependent on ________________________.

density _______ as temperature _______

Rearrange the formula for density to solve for each variable:

D = m = V =

52

Density Examples: What is the density of a block of marble with a mass of 594 g and a volume of 216 cm3? A 40.0 cm3 sample of quartz has a density of 2.65 g/cm3. What is the mass of the quartz sample? A density of a sample of cork is 0.24 g/cm3. What is the volume of this sample if it has a mass of 36g? A piece of granite has a mass of 0.055 kilograms and a volume of 20.0 cm3. What is the density of this piece of granite in g/mL?

53


Read pg. 89-92. Practice problems page 91-92 #46-48

46. A student finds a shiny piece of metal that she thinks is aluminum. In the lab, she determines that the metal has a volume of 245 cm3 and a mass of 612 g. Calculate the density. Is the metal aluminum?

47. A bar of silver has a mass of 68.0 grams and a volume of 6.48 cm3. What is the density of silver?

48. Use the factor label method and the given densities to make the following conversions.

a. 14.8 g of boron to cm3 of boron. The density of boron is 2.34 g/cm3. b. 4.62 g of mercury to cm3 of mercury. The density of mercury is 13.5 g/cm3.

54


Pg. 93 #51-56

51. How does density vary with temperature? _________________________________________________

____________________________________________________________________________________

52. A weather balloon is inflated to a volume of 2.2 x 103 L with 37.4 g of helium. What is the density of helium in grams per liter?

_________________

53. A 68-g bar of gold is cut into 3 equal pieces. How does the density of each piece compare to the

density of the original gold bar? ______________________________________________________

___________________________________________________________________________________

54. A plastic ball with a volume of 19.7 cm3 has a mass of 15.8 g. Would this ball sink or float in a

container of gasoline? Why? (hint: use table 3.6 on page 90)

55. What is the volume, in cubic centimeters, of a sample of cough syrup that has a mass of 50.0 g? The

density of cough syrup is 0.950 g/cm3. _________________________________________________

_________________________________________________________________________________

56. What is the mass, in kilograms, of 14.0 L of gasoline? (Assume that the density of gasoline is 0.680 g/cm3)

_________________

55

Measurement Review

Precision and Accuracy

1. From the information given, can you describe the precision and accuracy of the following scenarios? a. While in the chemistry lab fourth period, Cal Cium weighs his lunch. ______________________________

b. Ruth Enium, Maggie Nesium, and Cal's cousin Fran determine the density of water in g/mL. Their

results are as follows: 1.12 g/mL, 1.13 g/mL, and 1.12 g/mL. ___________________________________

2. If the average result of Ruth's, Maggie's, and Fran's work is 1.12 g/mL, calculate the percent error in their

experimental measurement of the density of water.

Significant Figures

3. Determine the number of significant figures in each of the following measurements.

a. 0.005040 g __________ d. 4.000 mm __________

b. 3.06 x 105 m __________ e. 5000 kg __________

c. 670. g __________ f. 47.060 mL __________

Rounding

4. Round the following measurements to the indicated number of SF's.

a. 5.5455 g to 3 SF _____________ d. 40.00 mg to 1 SF _____________

b. 0.0060104 cm to 4 SF _____________ e. 62.250 sec to 3 SF _____________

c. 4892 kg to 2 SF _____________ f. 800.48 g to 3 SF (2 ways) ___________ ___________

Scientific Notation

5. Convert the following measurements into either scientific or algebraic notation.

a. 0.0670 ng _______________________ c. 5.60 x 102 psec _______________________

b. 15100 cm _______________________ d. 6.780 x 10-3 ML _______________________

Calculations with Measurements

6. Perform the following operations, making sure to report the answer with the correct label and correct

number of SF.

a. 0.0640 g/ 2L = ____________________ d. 26 g + 4.0 g + 12 g = _____________________

b. (8.0 x 103 m) (4.30 x 105 m) = ________________ e. 5.76 x 103 g + 4.1 x 103 g = ________________

c. 300. cm2 / 0.60 cm = ______________________ f. 500 m + 4 m = ___________________________

56

Reading Instruments

7. For the instruments pictured below, determine their calibration, the estimation column, and finally, read

the instrument.

a. b. Calibration ___________

Estimation ____________

Calibration ______________ Estimation ______________

Reading ____________

Reading ________________

The Metric System

8. Complete the following conversions:

a. 7.65 μm = _____________________________m c. 834 g = ______________________________mg

b. 6.78 x 102 cL = _________________________dL d. 4.92 x 10-6 Msec = ___________________Gsec

e. If a proton weighs 1.66 x 10-27 kilograms, what is its mass in nanograms?

f. One gallon is slightly smaller than 4 liters. How many cubic centimeters is equivalent to four liters?

g. Express the speed of light, 3.0 x 108 m/sec, in cm/hr.

1 0 2 3

57

Measurement Practice Test

1. Significant figures in a measurement are

(a) only the first three numbers in a measurement.

(b) all digits known for certain, plus one estimated digit.

(c) all digits measured plus two more decimal places.

(d) dependent upon the unit.

2. Which of the following has the least significant figures?

(a) 12.19 x 10-3

g (d) 0.0165 mg

(b) 923.1 mg (e) 2.3340 x 10-6

kg

(c) 39000 cg

3. The number 6.33 x 102 equals

(a) 633 (c) 0.633

(b) 63.3 (d) 0.0633

4. Which of the following metric relationships is correct?

(a) 1 microliter = 106 liters (c) 1 megagram = 10

6 g

(b) 1 millimeter = 103 meters (d) 1 kilogram = 10

2 grams

5 If a measurement is precise and accurate, it is

(a) repeatable but not close to the true value.

(b) close to the true value but not repeatable.

(c) repeatable and close to the true value.

(d) not repeatable and not close to the true value.

6. Which of the following masses was measured on the most sensitive balance?

(a) 100.010 g (c) 0.03 g

(b) 10001.11 g (d) 3.00 g

7. How many zeros in the measurement 0.00004020 meters are NOT significant?

(a) 7 (c) 2

(b) 5 (d) 6

8. A large graduated cylinder is calibrated to the ones. The volume of liquid in this cylinder can be read to

(a) tens (d) ones

(b) tenths (e) hundreds

(c) depends on the size of the space between the calibration lines.

9. Record the correct answer for the following calculation: 9.60 x 102g / 3.2 x10

-8 cm

3

(a) 3 x 1010

g/cm3 (c) 3.0 x 10

10 g/cm

3

(b) 3.00 x 1010

g/cm3 (d) 3.0 x 10

-10 g/cm

3

10. Kerosene has a density of 0.8 g/ cm3

. What volume would 200 grams occupy?

(a) 300 cm3 (c) 160 cm

3

(b) 250 cm3 (d) 200 cm

3

58

Review: Match the correct term to each numbered statement.

_____11. An alloy can be classified as this type of matter.

_____12. A chemical reaction in which heat is absorbed from the surroundings.

_____13. A vertical column of elements on the periodic table.

_____14. Chemical formula for baking soda.

_____15. The elements on the periodic table with atomic numbers above 92.

_____16. Group IIA.

_____17. Type of matter that combines in a definite proportion.

_____18. A chemical reaction in which heat is released to the surroundings.

_____19. The piece of laboratory equipment is used to heat solids to a constant mass.

_____20. Radium is part of this family.

_____21. Group VIIA.

_____22. Group IA.

_____23. A horizontal column of elements on the periodic table.

_____24. Piece of laboratory equipment is used to separate a dissolved solid from a liquid.

True or False? If false, change the statement to make it true.

25. The hottest part of the Bunsen burner is the blue cone. __________

26. The inner transition element with the highest atomic number is mercury, #80. __________

27. The properties within a group vary from element to element. __________

28. Two elements exist as liquids at room temperature. __________

29. There are 7 periods on the periodic table. __________

30. Aluminum can be classified as a metalloid. __________

31. Air is a compound formed between nitrogen and oxygen. __________

Chemical or Physical?

32. Unwanted paper is placed in the shredder. ______________________

33. Frosty the snowman melts. ______________________

34. Methane is burned in the lab while using the Bunsen burner to heat a substance. ______________________

a. alkaline earth metal

b. alkali metals

c. halogens

d. noble gases

e. exothermic

f. endothermic

g. period

h. group/family

i. crucible & lid

j. evaporating dish

k. solution

l. compound

m. NaHCO3

n. transuranium

59

Name ____________________________________________________ Period ___________________

MEASUREMENT - Vocabulary Review Match the correct vocabulary term to each numbered statement. Write the letter of the correct term on the line. Each answer can only be used once. a. accuracy g. exact numbers l. significant figures

b. measurement h. actual value m. kilogram

c. experimental value i. conversion factor n. error

d. calibration j. factor label method o. density

e. percent error k. uncertainty p. kelvin f. precision ___________ 1. The difference between the actual value and the experimental value.

___________ 2. A quantity that has both a number and unit.

___________ 3. A value obtained from the lab and from a measuring device.

___________ 4. A measure of how close a series of measurements are to one another.

___________ 5. The value of the smallest line on the measuring device.

___________ 6. Are counting numbers and definitions.

___________ 7. A correct value based on reliable references.

___________ 8. A technique of problem solving that changes the units of measurement by

multiplying by a factor of one.

___________ 9. All digits known for certain, plus one estimated digit.

__________10. The ratio of the mass of an object to its volume.

__________11. A ratio of equivalent measurements used to convert a quantity from one unit

to another.

__________12. A measure of how close a measurement comes to the actual value.

__________13. One decimal place to the right of the calibration on a measuring device.

__________14. The percent that a measured value differs from the accepted value.

__________15. The SI Unit for measuring mass.

__________16. The SI Unit for measuring temperature.

61

Measurement Mania I. General Measurement.

1. Which is larger? Circle your choice.

a. 1 mile or 1 kilometer k. 1 kilogram or 1 pound

b. 1 pound of 1 gram l. 1 liter or 1 quart

c. 1 liter or 1 gallon m. 1 inch or 1 centimeter

d. 1 yard or 1 meter n. 1 ounce or 1000 milligrams

e. 1 meter or 105 centimeters o. 4 kilometers or 4400 meters

f. 1 kilogram or 1500 grams p. 1200 milligrams or 1 gram

g. 12 centimeters or 102 millimeters q. 1200 millimeters or 1 meter

h. 12 milligrams or 12 kilograms r. 4 kilograms or 4500 grams

i. 1 liter or 1500 milliliters s. 200 milliliters or 1.2 liters

j. 12 cm3 or 1.2 milliliters t. 1 gallon or 2 liters

2. The SI unit for measuring length in the metric system is the _________________, and is

represented by the lower case letter, _____________.

3. The SI unit for measuring mass in the metric system is the _________________, and is represented

by the letters, _____________.

4. The SI unit for measuring the amount of substance in the metric system is the _________________,

and is represented by the letters, _____________.

5. What instrument in the lab should one use to measure liquid volume?________________________

6. What instrument in the lab should one use to measure mass? _______________________

7. What instrument in the lab should one use to measure length? _______________________

8. What is the formula used to find the volume of a block? _______________________

9. Estimate the length and width of your desk in centimeters. _______________________

10. Estimate the length and width of the room in meters. _______________________

11. Estimate your mass in grams. _______________________

62

II. Factor Label Method (Dimensional Analysis). Use the factor label method to solve the following problems. Report your answers to 2 significant figures.

12. On your 16th birthday, what is the total number of seconds you have lived?

13. Express the length of a football field (100 yards) in inches.

14. How many basketballs can be carried by 8 buses? (1 bus = 12 cars; 3 cars = 1 truck;1000 basketballs = 1 truck)

III. Significant Figures.

15. How many significant figures are in the following measurements?

a. 542 g ________ c. 0.00542 g ________

b. 5420 g ________ d. 542.00 g ________

16. Use the ruler and line below to answer the following questions.

a. What is the length of the line in centimeters? ______________________________

b. What is the length of the line in millimeters? ______________________________

c. Estimate the length of the line in inches. ______________________________

IV. Scientific Notation. Express the following in either scientific notation or algebraic notation.

17. 2500000000000 _________________________

18. 0.000000456 _________________________

19. 4.25 x 10-5 _________________________

20. 7.02 x 108 _________________________

21. 40500000 _________________________

63

Reliability of Measurements

Introduction: When scientists make measurements, they evaluate both the accuracy and precision of the measurements. Accuracy refers to how close a measured value is to the accepted value; precision refers to how close a series of measurements are to each other. In this lab, you will examine the accuracy and precision of three different tools used for measuring. A 250-mL beaker, a 100-mL graduated cylinder, and a 50-mL buret will be used to make the measurements. Materials 250-mL beaker 600-mL beaker 50-mL buret buret clamp ring stand water funnel eye dropper 100-mL graduated cylinder balance Procedure: Part A 1. Obtain a 250-ml beaker and a 600-mL beaker.

Fill the large beaker with water. 2. Mass the 250-mL beaker; record in Table A. 3. Measuring as accurately as possible, pour 50 mL

of water into the beaker. Mass the beaker and water; record in Table A.

4. Pour the water out of the beaker; dry the beaker.

5. Repeat steps 2 - 4 two more times for a total of three trials.

6. Although the beaker can be read only to the tens column, we are going to assume that the volume of the water is 50 mL for all three trials.

PART B 1. Mass your 250-mL beaker; record in Table B. 2. Measuring as accurately as possible, pour 50

mL of water into a 100-mL graduated cylinder. If necessary, use an eye dropper to make sure that the bottom of the meniscus is “exactly” on the 50-mL line. Record the volume in the data table (remember significant figures). The volume will be the same for all three trials.

3. Pour the water into the dry beaker. Mass the beaker and water; record in Table B.

4. Pour the water out of the beaker; dry the beaker.

5. Repeat steps 1 - 4 two more times for a total of three trials.

PART C 1. Obtain a buret and buret clamp. Secure the

buret in the clamp attached to a ring stand. 2. Mass your 250-mL beaker; record in Table C. 3. Using a funnel, slowly fill the buret to the 0-

mL line. (To do this, fill slightly past the 0-mL mark and drip out the excess until the bottom of the meniscus is on the 0-mL line.)

4. Place the 250-mL beaker under the buret. Open the stopcock on the buret and slowly drain 50-mL of water into the beaker. CAUTION: As you approach the 50-mL line, drain the water from the buret drop by drop until the bottom of the meniscus is on the 50-mL line.

5. Mass the beaker and water; record in Table C. 6. Pour the water out of the beaker; dry the

beaker. 7. Repeat steps 2 -5 two more times for a total of

three trials. 8. In Table C, record the 50-mL of the water

measured with the buret to the correct number of significant figures. This will be the same for all three trials.

Water, Water Everywhere

65

Name _____________________________________________________________ Period _________

Table A – Beaker Measurements

Mass of Beaker

Mass of Beaker And Water

Mass of Water

Volume of Water

Trial 1

Trial 2

Trial 3

Average

Table B – Graduated Cylinder Measurements

Mass of Beaker


Mass of Water

Volume of Water

Trial 1

Trial 2

Trial 3

Average

Table C – Buret Measurements

Mass of Beaker


Mass of Water

Volume of Water

Trial 1

Trial 2

Trial 3

Average

66

CONCLUSION: 1. The known mass of 1.00 mL of water is 1.00 grams. For this experiment, what mass should you

expect for each of your samples?______________________________________________________

2. Using your answer to #1 as the accepted value and the average mass of water as your

experimental value, calculate the percent error for Part A, B, and C. SHOW YOUR WORK! 3. Explain how you decided how many significant figures were needed for the volume

measurements made with the graduated cylinder and buret. __________________________

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

4. Which of the three measurement tools produced the most accurate results? Explain, using the

definition of accuracy in your answer. ____________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

5. Which of the three measurement tools produced the most precise results? Explain, using the

definition of precision in your answer. _______________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

67

OLYMPIC SYMBOL Five interlocking rings represent the five major continents of the world. Their colors in order from left to right are: blue, yellow, black, green, and red. These colors are special because at least one of them appears in the flag of every nation of the world. These colorful rings are joined together to remind us of the sporting friendship of all mankind. HISTORY: ANCIENT GAMES Traditionally the accepted date of the first Olympiad is 776 B.C. but there is reasonable certainty that they were held considerably earlier than that. These festivities were held in Olympia, Greece, where a stadium and a temple to Zeus were built. On selected occasions “a day of games” was held to honor a god or a dead hero. Only males were allowed to participate and events originally included a foot race, also called the stadium race, a long distance foot race, wrestling, and the pentathlon which was a combination of five events. The ancient games ceased to take place after 392 A.D. because they were viewed by Christians as a pagan ritual. THE OLYMPIC MOTTO: Citius, Altius, Fortius From the Latin meaning swifter, higher, stronger, these words are used to build healthy attitudes

and winning spirits in preparation for competition. THE OLYMPIC FLAME The Olympic flame is lighted by the Olympic torch during the opening ceremonies. The flame is a symbol of peace and is lit first in the temple of Zeus in Olympia. Thousands of relay runners from many countries then carry it to the stadium of the city hosting the games. The flame is passed by hand from one runner to the next. MODERN OLYMPIC GAMES Credit for the revival of the Olympic Games goes to Pierre de Coubertin, a French baron who felt strongly about bringing together representatives from many nations for the purpose of peaceful competition. He posed these words that now make up the Olympic creed: “The most important thing in the Olympic Games is not to win but to take part, just as the most important thing in life is not the triumph but the struggle. The essential thing is not to have conquered but to the have fought well.” With respect and honor to Greece, the land of the original games, the first modern games were held in Athens in 1896 where nine countries came together. The 1988 Olympic Games were held in Seoul, South Korea where 161 countries competed in 23 Olympic Sports. Winners in each event earned

68

gold, silver and bronze medals for their performances. Each athlete made this pledge: METRIC OLYMPICS Similar to the traditional Olympic Games, the Metric Olympics strive to challenge each participant, bring out the spirit of competition and good sportsmanship, and build team camaraderie. But unlike the sports-centered Olympic events, the Metric Olympics will not only test your athleticism and skill, but also your intellectual and scientific abilities. The events will focus on the specific skills of estimation and measurement. The metric system will be the system of measurement used in all events in these Olympics. There are six events in which you will compete:

1. Paper Straw Javelin Throw 2. Paper Plate Discus 3. Cotton Ball Shot Put 4. Right-Handed Marble Grab 5. Left-Handed Sponge Squeeze

6. Big Foot Was Here!

REQUIRED SKILLS Measuring in metric units Estimating Predicting

PROCEDURE 1. There are a total of six stations. At each

station you will find a note card with complete instructions.

2. Each competitor should read the instructions before completing each activity.

3. Only rotate events when your teacher announces that it is time.

4. Each student is responsible for making their own estimates, measurements and recording their own data.

5. Clean up each station before rotating to the next event.

CONCLUSION:

1. Each competitor: complete the data table. Remember to use the correct number of significant figures and make sure each estimate and measurement has a unit. SHOW ALL WORK FOR CALCULATIONS (i.e. area, error and % error)!!

2. Answer the conclusion questions that are on the back of the data table.

69

Competitor __________________________ Team Name ________________________

EVENT Guess

ACTUAL

ERROR % ERROR

Paper Plate Discuss

Paper Straw Javelin

Cotton Ball Shot Put

Right-Handed

Marble Grab

Left-Handed Sponge Squeeze

Big Foot Contest

l = ______ w = ______

A = ______

l = ______ w = ______

A = ______

(Area only) (Area only)

Average % error

|error|

actual x 100 (ones column)

(3 sig figs)

guess - actual

70

Conclusion

1. Describe how you determined the number of significant figures to use in the “distance” and “volume”

measurements. _______________________________________________________________________

____________________________________________________________________________________

____________________________________________________________________________________

2. Describe how accuracy is related to the % error that you calculated. ____________________________

____________________________________________________________________________________

____________________________________________________________________________________

3. Use the factor label method to convert your actual measurements to the following metric units (use your data). SHOW ALL WORK & PAY ATTENTION TO SIGNIFICANT FIGURES FOR FULL CREDIT!

a. __________ cm __________ mm

b. __________ g __________ ng

c. __________ mL __________ ML

d. __________ cm2 __________ m2

4. Estimate the length and width of the laboratory in meters. _________________________

5. Estimate the mass of a pencil in grams. ____________

6. Estimate the length of your arm span in cm. ____________

71

CSI: Fahrenheit 932

Name ___________________________________________________________ Period ____________ Directions: Indicate whether the following statements are TRUE (T) or FALSE (F) in the “before” column before the video plays; then, while the video is playing, respond in the “During” column.

Before Statement During 1. Gasoline is a hydrocarbon. 2. It gets cold at night in Las Vegas. 3. No one should touch a crime scene until after a CSI has been there. 4. The initial hypothesis for the reason that the young man was attacked

was robbery.

5. Condensation is moisture droplets collected on a surface. 6. General rule of thumb: one inch equals $2500. 7. Foot prints are better than shoe prints. 8. At 6320 F smoke turns to fire in the presence of oxygen. 9. Gasoline is not an accelerant. 10. Kids playing with matches cause a lot of fires. 11. Fire feeds O2. 12. Fire is lazy—it will always take the path of least resistance. 13. Fire burns up and out—in a V pattern. 14. A narrow V is indicative of an intense and slowly moving fire. 15. Glass cannot melt. 16. Spawling confirms the use of an accelerant. 17. Scientists consider only the evidence that proves their hypotheses. 18. The mini, “flash over” takes place in an Erlenmeyer flask. 19. Scientists run experiments to discover new information and confirm

facts.

20. “Alligatoring” is a term that describes a burn pattern. 21. You should always check for heat & smoke before opening a door in a

fire.

22. CO is a poisonous gas. 23. Another hypothesis for Joey’s death is revenge on his brother Danny for

stealing money.

24. There are 30 matches in a pack of waterproof camping matches. 25. DNA is a good identifier. 26. Glass must be at least 10000 F to melt. 27. Any hydrocarbon can be an accelerant. 28. You should always cover your mouth before you sneeze.

73

WHAT dO I need to know?? Unit 3: Scientific Measurement

Accuracy vs. Precision

analyze a set of data and describe its

accuracy and precision

Reading Equipment

Graduated cylinder (“Reading Instruments”)

Ruler (“Reading Instruments”)

Element Review

names & symbols

Temperature Conversion

0C K

Most Wanted List

Old and new

Past lab questions that were missed on the last test (HINT: what

does “solution” indicate about a substance)

The Metric System

all of the prefixes & units

conversion factors

Significant Figures

Definition

You must use the appropriate number of sig figs on all problems

Know the rules for calculating with measurements

74

Density

Know the formula

Solve for density

Solve for volume

Solve for mass

% error

Know the formula and how to solve it

Scientific Notation

You will be required to place several of your answers in scientific

notation

3 conversions

o cm3 L

o m/s km/hr

o Solve for volume (given the density in g/cm3 and the mass

in mg).

Review: Chemistry is a subject that builds upon prior knowledge.

You are responsible for anything that has been covered on previous

tests.

physical vs. chemical changes

organization of the periodic table (groups vs. periods; names of

common groups)

heterogeneous vs. homogeneous types of matter

element names and symbols

Unit 3: Scientific Measurement · Unit 3: Scientific Measurement (Chapter 3) 2 Chemistry Math...

Documents

Transcript of Unit 3: Scientific Measurement · Unit 3: Scientific Measurement (Chapter 3) 2 Chemistry Math...