Significant Digits and Metric Conversions!

CHEMISTRYUNIT 4 REVIEW

PART 1

How Many? Conversions Add/Subtract Multiply/Divide Mix It Up!

10 10 10 10 10

20 20 20 20 20

30 30 30 30 30

40 40 40 40 40

50 50 50 50 50

Question 1 - 10

• How many significant Digits are in this number:

1422

Answer 1 – 10

• 4!• All numbers present are between 1 and 9.

Question 1 - 20

• How many significant digits are in the following number?

200

Answer 1 – 20

• There is only 1!

• The zeros don’t count because the number doesn’t have a decimal place in it!

Question 1 - 30

• How many significant ZEROs are in the following number?

0.0030050

Answer 1 – 30

• 3!• The captures zeros and the trailing zero are

the only ones that are significant!

Question 1 - 40

• What is the length of the following green bar?

Answer 1 – 40

• 1.25!• The 1 and the 2 are in concrete, the 5 can be a

different number that is reasonable.

Question 1 - 50

• How many zeros in the following number are NOT significant?

.0005050090

Answer 1 – 50

• 3!• Only the zeros in the beginning of the number

do not count!

Question 2 - 10

• Convert the following:

254.3 grams to Kilograms

Answer 2 – 10

• .2543 Kg

• The number will get smaller because the unit gets bigger!

Question 2 - 20

• How many milliliters are in the following number?

0.0367 Liters

Answer 2 – 20

• 36.7 mL

• The number gets bigger because the unit gets smaller!

Question 2 - 30

• Which weighs more?

4.25 grams of Au or425 mg of Au

Answer 2 – 30

• 4.25 grams does!

• Convert milligrams to grams and you get .425 mg! That is less than 4.25 grams!

Question 2 - 40

• What is the metric prefix that correspond to the following quantity?

10-2

Answer 2 – 40

• Centi!

Question 2 - 50

• How many mL are in the following number?

87 DL

Answer 2 – 50

• There are 870,000 mL!

• KHD*dcm

Question 3 - 10

• What is the answer to the following addition problem?

212.2 + 26.7 + 402.09

=

Answer 3 – 10

• Addition, so look for least # of decimal places!

• 641.0

Question 3 - 20

• What is the answer to the following addition problem?

2.01x102 + 3.014x103

Answer 3 – 20

• 3215

• You have to take the numbers out of scientific notation to look at decimal places!

Question 3 - 30

• What is the answer to the following problem?

52.331 + 26.01 – 0.9981

Answer 3 – 30

• 77.34

• Watch number of decimal places here! Add and subtract carry least number of decimal places to the answer.

Question 3 - 40

• How many digits after the decimal point should be reported when the following calculation is performed?

199.0354 + 43.09 + 121.2

Answer 3 – 40

• There should only be 1 decimal place in this answer!

Question 3 - 50

• How many digits after the decimal place should be reported when the following calculation is performed?

10,434 – 9.3344

Answer 3 – 50

• There will not be any decimal places in this number!

Question 4 - 10

• What is the answer to the following division problem?

12.011 / 6.022x1023

Answer 4 – 10

• 1.995x10-23

• We need to look at number of significant digits in the numbers of the problem—least number determines answers sig figs!

Question 4 - 20

• What is the answer to the following problem?

(4.031)(0.082068)(373.1)/.995

Answer 4 – 20

• 124

• Remember least # of sig figs will be reported in the answer!

Question 4 - 30

• The answer to the following question should be written with how many significant digits?

2.3733x102/343

Answer 4 – 30

• 3!

Question 4 - 40

• When the following calculation is performed, the answer should be reported with how many significant digits?

.0043*.0821*298

Answer 4 – 40

• 2!

• Remember least goes!

Question 4 - 50

• What is the answer to the following problem?

(6.1982x10-4)2

Answer 4 – 50

• 3.8418x10-7

• Or 3.8000x10 -7

Question 5 - 10

• What is the answer to the following problem?

(2.0944+.0003233*12.22)/7.001

Answer 5 – 10

• .2997

• Remember your order of operations!• Please Excuse My Dear Aunt Sally!

Question 5 - 20

• What is the answer to the following problem?

[(1.42x102)+(1.021x103)]/3.1x10-1

Answer 5 – 20

• 3.8x103

Question 5 - 30

• Consider the following numbers 23.68 and

4.12. • The sum of these numbers has how any

significant digits?• The product of these numbers has how many

significant digits?

Answer 5 – 30

• Sum has 4• Product has 3

Question 5 - 40• You pour the water from these beakers into a

separate container. What is the volume with the correct number of significant digits.

Answer 5 – 40

• Your answer should range from 81 to 82 mL without any decimals!

Question 5 - 50

• Report the volume of the water in each beaker with the proper # of significant digits.

Answer 5 – 50

• I has 26.4(ish) mL• II has 28(ish) mL• III has 26.42(ish) mL

• The –ish comes from your interpretation. Remember the first digits are known and the last digit is an educated guess (is it uncertain).