Welcome to General Chemistry 151!!

Instructor: Dr. Lauren BenzST-378

Chem 151 / Chem 151L

1. This course is intended for science majors/engineering majors/pre-health students, not a GE.

2. Lecture and lab are co-requisites. • If you are not enrolled in both lecture &lab (and if you have not previously If you

are not enrolled in both lecture &lab (and if you have not previously passed one or the other), you will be dropped from 151/151L after add/drop deadline has passed.

3. If you are able to register for a spot in lab, you may then add Chem 151, but you cannot register for Chem 151 without being enrolled in a Chem 151L lab.

• Please contact Mrs. Finocchio. Provide name, email, phone, and CRNs of 151/151L sections you are trying to get.

If you have questions, contact Mrs. Finocchio in SCST 381/ debbief@sandiego.edu.

Chem 151 / Chem 151L

Chem 151L lab announcements:

No G Chem lab this week.

Watch for an email from your lab instructor regarding your first day of lab and what to bring.

The class requires lab spectacles and model kits, which the Chem Club is selling (see schedules posted). Cash or check only.

Textbook and MasteringChemistryBookstore: • New customized textbook with MasteringChemistry access code (with 4

year access) packaged together = $175.95. • “customized” = any chapter we don’t use has been removed to help

lower cost of book.• Located at front end of left aisle. Ask if you cannot find it!

www.masteringchemistry.com: • Can purchase MasteringChemistry access code directly, with or without

e-text.• With e-text = $110.00• Without e-text = $66.00

• Do this option if you have a textbook but don’t have MasteringChemistry yet, or if you don’t want to purchase a printed book and just want the e-text.

• This MasteringChem will have the standard 24 months access.

Other sources:Non-customized version of textbook (various prices) – the book will have the same page numbers, etc, just a few extra chapters we don't use.

Emergency Preparedness

Evacuation Procedure for SCST 133

Primary exit: Via the exits on the first floor: turn left when exiting the room and walk out the exit at the end of the hall. DO NOT go up the central staircase! We will meet in front of La Paloma. Wait there for further instructions (please do not wander off).

DO NOT stand in the street outside the building - the street must remain clear for emergency vehicles.

Expectations for Chem 151:

1. Attend all lectures- Be on time, and please sit in the back if you

must leave early- Be courteous to me and others (no texting,

no cell phones, no unauthorized work on computers, tablets, etc.)

2. Keep up with the reading & work recommended problems (+ more, time commitment = 2-3 hours per lecture)

3. Ask questions4. Prepare for tests—rework problems,

work additional problems and practice exams

Support1. Office hours: 5 hours/week

+ by appointment2. Outside support: chem club

tutoring, math center3. I will help pace the

workload, and give additional practice before exams

4. I will try to make it interesting!!!

Chemistry: the study of matter• Nuclear chemistry (fusion, fission)• Organic chemistry (pharmaceutical

industry, chemical synthesis)• Analytical chemistry (uses

instrumentation to study various problems—air & water pollution)

• Biochemistry (biotech companies)• Inorganic chemistry (materials,

catalysis, etc.) • Physical chemistry (spectroscopy,

microscopy, etc.) • Computational chemistry (for those

who don’t like touching chemicals! Make predictions from theory..)

• Other: science writing (Scientific American, etc.), patent law, policy, medical school

Combinations of these“Interdisciplinary”

In order to do controlled experiments in chemistry (or any science really) we

need to quantify!

Multiples of SI units:1 TW = 1 terawatt (the power of a lightening strike)

15 TW = the annual energy consumption of the world

Deciliter- in Europe! 3 dL ≈ 12 fl. oz

100 µm = 1 human hair

0.2 nm ≈ space between Au atoms (in solid form)

To read this chart:“There are 1012 grams in a teragram, 10-12 seconds in a picosecond” and so on.

Need to remember:

• 1012 Watts in one TW• 109 Watts in one GW• 106 Watts in one MW• 103 Watts in one kW

• 10 deciliters in 1 L• 100 centimeters in a meter• 1000 millimeters in a meter• 106 micrometers in a meter• 109 nanometers in a meter• 1012 picoseconds in a second• 1015 femtoseconds in a second

Larger units: Smaller units:

1.21 Gigawatts!!

Some definitions…• Mass: the amount of matter in an object.

**Not to be confused with “weight” which measures the force with which gravity pulls on an object

• Temperature: a measurement of the kinetic energy of molecular motion (more detail to come in Ch. 8)

Temperature conversions

What is larger: one degree C or one degree F? one degree C or one K?

Temperature conversion formulas• To convert from °C → °F

°F = (9°F /5°C ) x °C + 32°F

• To convert from °F → °C°C = (5°C /9°F) x (°F - 32°F)

• To convert from °C → KK = °C + 273

• To convert from °F → K– First convert to °C, then to K

Remember “PEMDAS”:(order of operations)

1. Parentheses2. Exponents3. Multiplication/division4. Addition/subtraction

(variables are in red)

Derived units

• Unlike the fundamental units (like mass and temperature), derived units involve a combination of more than one fundamental units– Examples: area (m2), volume (m3), density

(kg/m2), acceleration (m/s2), force (kgm/s2 or “Newton”), energy (kgm2/s2 or “Joule, J” )

Density of some common items

DEMO: CO2 (25°C) = 0.001801 g/cc3????????

Density = mass/volumeNote: 1 cm3 is a cubic centimeter, sometimes called “cc” and is equal to 1 mL

Energy• Kinetic Energy: energy of a moving object

KE = (1/2)mv2 ; m = mass and v = velocityunits: kg m2/s2 = 1 Joule

• Potential Energy: stored energy (can have many forms, can be due to an object’s height or can be in the form of chemical energy)

Significant Figures + Rounding

• See rules in Ch. 0• Refer to class handouts• When reading glassware…estimate out to

one extra place!!

1mL

5mL

3.3 mL

Scientific Notation

Definition: Method of simplifying the writing of very large and very small quantities

How to express: Find the number, which when multiplied by 10x, will give you the number written in the "normal" style

(Examples on board)

Conversions(dimensional analysis)

1. Write down the number that you want to covert2. Write down your conversion factor(s) to the right of

the number—make sure that you place your units so that they will cancel

3. Cancel units and multiply or divide (your remaining unit should be the one that you are converting to)

4. Double check whether or not the answer is reasonable.

** Note: if your conversion involves a derived unit such as meters squared (m2), you must also raise the conversion factor to the power of the unit (in this case 2)

Example

• A human hair is approximately 100 µm in diameter. Convert this into meters.

• A football field is 48,000 ft2. How many square meters is that?

Conversions (cont’d)

• Another unit of energy is the calorie:– 1 calorie = 4.184 J– 1 Calorie = 1000 calories (note the upper and

lower case distinction—”Calories” are what are listed on food packaging)

Please make note of these two conversions for the group exercises..

The Mole!! • The mole is actually a measure of a number

of things (abbreviated “mol”)• In the same way that a “dozen” contains 12

things, a mole contains 6.022 x 1023 things• Definition: 12 grams of C (in it’s most

common form, 12C) contains 6.022 x 1023 atoms

• The #s below the elemental symbols on the periodic table give an elements “molar mass”, the mass of 1 mole of the pure element (can be read as “## grams/mole)

Unified atomic mass unit “(u) or (amu)”

• Another way to read the numbers on the periodic table

1 amu =

= 1.66 10-24 g

Momolybdenum

42

95.94

Calculations involving the mole

• A small silicon chip used in a microcomputer has a mass of 5.68 mg.

– How many moles of Si (atoms) is this? – How many Si atoms are present in this chip

Accuracy & Precision

• both are considered to be general measurements of uncertainty

• Accuracy: refers to how close to the true value a given measurement is

• Precision: refers to how well a number of independent measurements agree with one another

Which one is more precise?

Better accuracy Better precision

The Periodic Table• To the left of the red line: mostly metals (shiny, conductors of electricity & heat)• To the right of the red line: mostly non-metals (most are gases, solids are brittle)• Exceptions: circled in blue, “semi-metals” (B, Si, As, Te, At, Ge, Sb—all solids)

http://www.nist.gov/pml/data/periodic.cfm

A Brief History• Prior to 1000 BC: metals were extracted

from ores to form ornaments & weapons, embalming fluids

A Brief History• Prior to 1000 BC: metals were extracted

from ores to form ornaments & weapons, embalming fluids

• 400 BC » Greeks proposed “fire, earth, water, air”

» Democritus believed in “atomos”-indivisible particles

• Next 2000 years: alchemy, however mercury (Hg), sulfur (S) and antimony (Sb) were discovered

• Mid 1700s: Joseph Priestly discovered oxygen• 1829: Johann Doebereiner put together

“triads” of similarly behaving elements• 1860: Dimitri Mendeleev arranged the

elements by mass and grouped similar elements together—realized that some were missing, undiscovered

Chemistry is relatively young!

“Chemical Geneology”

1.Lauren Benz, Ph.D., 20072.Cynthia Friend, Ph.D., 19813.Earl Muetterties, Pd.D., 19524.Eugene Rochow, Ph.D., 19355.Luis Monroe Dennis, B.S., 18866.Walther Matthias Hempel, Ph.D., 18737.R.W.H. Bunsen, Ph.D., 1830

…keeps going back to 1640

from left to rightrows arecalled “periods”

going up and downthe columns are called“groups”

The Periodic TableElements in the same group typicallyhave similar properties.

Main groups(green-shaded)

Transition metal groups(yellow-shaded)

http://periodictable.com/Elements/Source-harvardMuseum/index.html

The Periodic Table:main group elements (1A-8A)

Group 1A: “Alkali Metals”: REACTIVE!! all react with water to form basic (or alkaline) solutions. Soft, silvery You can visualize this by adding an “indicator” which turns pink when the solution becomes basic. Ex. Li, Na, K, Rb, Cs, Fr

Group 2A: “Alkaline Metals”: less reactive than 1A metals but also reactive. Also shiny. Ex. Be, Mg, Ca, Sr, Ba, Ra

The Periodic Table:main group elements (1A-8A)

http://www.youtube.com/watch?v=qSr39UwpELo

A Magnesium (Mg) strip burning:

The Periodic Table:main group elements (1A-8A)

Group 7A: “Halogens”: colorful, corrosive nonmetals. Ex. F, Cl, Br, I(in demo—blue color is from a complex of iodine)

The Periodic Table:main group elements (1A-8A)

Group 8A: “Noble Gases”: all colorless and inert. Ex. He, Ne, Ar, Kr, Xe

Chemical property: characteristic that involves a change in chemical make up

(1) demo ? (reaction involving color change)(2) demo ? Potassium (K) reaction with water

Physical property: characteristic that does not involve a change in chemical make-up (boiling point, melting point, density)

Demonstration: liquid nitrogenBoiling point (°C)? - 196°C!!!