Chemistry 100: Exam 1 Topics
History & Introduction
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Greeks & Alchemists: How did they
approach science? What did they
contribute?
Scientific Method
Chapter 1
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matter, change
pure subst, element, compound, mixture,
homogenous, heterogeneous, atom
Periodic table, chemical formulas
(interpret C2H6 as 2 carbons, 6
hydrogens)
PT: period, family=group=column
Atomic Number (Z), #p, #n, #e-,
atomic/nuclear symbol, mass number
(A)
Chemical/Physical properties & changes,
physical state, boil, freeze, evaporate,
sublime, melt, condense
PT: metal/nonmetal, family names
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Chapter 2: Molecular Subst., Lewis
Structures
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molecules, diatomic elements
(HONClBrIF)
Naming molecules (mono-, di-, tri-, …)
Skip mono- for 1st element
H2O is dihydrogen monoxide OR
“water”
Lewis structures: dots = valence eCovalent bond = shared eBonding pair, lone pair
Use handout method to draw Lewis
diagrams from scratch (but don’t have to
memorize the steps!)
Chapter 3: Ionic Compounds
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Ionic Bond – stolen electrons, (+) & (-)
stick together.
Extended structure
What ion will an element form (gain/lose
e- to get full/empty valence).
Charge Balance
Determine formula from ions. e.g.
Ca2+ Cl- use cross to get Ca1Cl2,
simplify to CaCl2
Naming: name cation, space, anion-ide
Polyatomic Ions
o Memorize list – name, formula, # ox,
charge
o –ate, -ite
o Which 5 elements did we base things
on?
o Others: NH4+, H3O+ (only cations),
CH3COO-/C2H3O2o Add 1 hydrogen (logically H+),
HSO4- = hydrogen sulfate ion
Oxidation Numbers
o just the charge of an ion
o decode using simple rules (known
ions are Grp I, II, Al3+, VI, VII). e.g.
PbO2, known Ox = -2, Pb must be 4+
o Don’t do ox # inside polyatomic
ions.
o Naming transition element ions:
PbO2 is lead(IV) oxide
Chapter 4
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Measurement – feet, inches, pounds, etc.
vs. Counting
Dozens & Moles
1 mol = 6.021023=
602,000,000,000,000,000,000,000
Ratio of hydrogen atoms to oxygen
atoms in H2O (2:1), ratio of moles of
atoms (2:1)
Chemical Reaction equations:
o reactants  products
o balancing (easy versions)
o what is a balance equation?
o Stoichiometry – ratios of # reactants
to # products or other reactants
o Matches worksheet.
Version A
Team Copy
Good Test Taking Skills
(Use these techniques to get 10-20 percentage points better scores.)
Process
1. Start with your name (build confidence)
2. Scan the whole exam.
a. If you see an easy question (10 seconds work time), do it.
b. Put an arrow next to any questions that you know how to do but will take more time.
DON’T DO THEM YET!
c. Put some other mark next to questions you think will be hard.
3. Go back and do the problems from 2b. If it turns out to be harder avoid getting bogged
down.
4. Finally start working on the harder problems. Try to do the easier first. If you get stuck,
move on.
5. If you finish early or the proctor announces 5-10 minutes, you can improve your score (on
average) by checking your work.
a. Make sure you have the right # of sig. figs.
b. Did you give units?
c. Be sure you answered the right question. Sometimes harder problems hide the actual
question.
INDIVIDUAL PROBLEMS
 The first rule it to avoid getting bogged down. If it's too hard, move on & come back later.
 Start a problem by identifying the actual question, note the required units if it's a calculation.
 Use the problem solving steps from Unit C.
 Avoid getting bogged down. If it's too hard, move on & come back later.
 If there's a chemical reaction involved, write it out.
 For essay/short answer question, write anything you know but avoid contradicting yourself.
Writing neatly will generally result in a better score - the grader will be happier with you.
Graders usually look for key phrases, be sure to use them.
 For multiple choice problems:
 Watch out for negative questions (which is NOT polar?)
 Usually avoid "none of these" You need to be sure before selecting this. If in doubt
guess on the other ones.
 As you read the problem, cross out any obviously wrong questions.