American Chemical Society (A.C.S) General Chemistry Exam
70 multiple choice questions, 110 minute
Bring a Scantron, calculator and pencil(s)
Preview for ACS-Standardized final Exam
1. 70 Multiple Choice questions, 110 minute. Bring a Scantron, calculator and pencil(s)
2. Scoring is based on correct answers. If you don’t know the answer, it pays to guess. It especially
pays to rule out one or two obviously incorrect answers, even if you aren’t sure about which
answer is actually correct.
3. Total time will be 110 minutes. This means you have 1 minute and 34 seconds per question.
Time management is important, but most students complete in time. A more common error
than going too slow is to work too fast, hurrying early in the test and not taking enough time to
carefully read through the questions and look at all the answers. I think it is foolish to every
leave before time expires on a multiple choice exam, because the time wasted by leaving early
will usually be enough to have rechecked several guess problems and to have eliminated some
impossible answers. If time permits, you would like to answer the problem on your own, and
then see if your answer matches on of the listed alternatives.
4. There are likely going to be questions that you do not know. While you will not get them all right
(a student can totally guess on 15 questions and still get an A!), the key is that you get at least
some of the questions absolutely certain, and can make an educated guess on a reasonable
portion of the rest.
5. Scores, percentiles, and Grades. The statistical analysis is based on the performance of 1,000
students. Shown below are some raw scores with the corresponding nation percentiles, and the
grade that will correspond.
RAW Percentile Grade
RAW Percentile Grade
RAW Percentile Grade
Score Rank
Recorded
Score Rank
Recorded
Score Rank
Recorded
10
0%
15
33
31%
75
52
90%
100
17
2%
20
34
34%
75
53
92%
100
(17.5 should be the statistically
35
38%
75
54
93%
100
average score of a monkey
guessing!)
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
3%
3%
4%
5%
6%
7%
9%
10%
12%
14%
16%
19%
22%
24%
28%
25
30
35
40
45
50
55
55
60
60
65
65
70
70
70
36
41%
80
37
45%
80
38
49%
80
National Average is 38.3
39
53%
80
40
56%
80
41
60%
85
42
64%
85
43
67%
85
44
71%
90
45
74%
90
46
77%
90
47
80%
90
48
82%
95
49
84%
95
50
87%
95
51
89%
95
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
94%
95%
96%
97%
98%
98%
98%
99%
99%
99%
99%
100%
100%
100%
100%
100%
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
TOPICS THAT FREQUENTY APPEAR ON THE ACS STANDARDIZED TEST
States of matter
 Ideal Gas Law: pV=nRT, pM=dRT, deviations from ideal (high P, low T)
 Ionic solids: simple cubic, face centered cubic, body centered cubic
 Phase diagrams: Pressure versus temperature
 Intermolecular Forces: ion-diope, hydrogen bonding, etc.
II. Stoichiometry and Thermochemistry
 Hess’s Law and Enthalpy: “standard states” have ΔHf0= 0
 Percent composition: %C, %H, etc.
 Combustion analysis
 Limiting Reactants
 Stoichiometry
III. Atomic Structure and periodicity
 Oxidation states of “main group” elements (Li, Be, B, etc)
 Oxidation numbers
 Electron configurations and relation to groups on periodic table (ns2np5=halogens)
 Periodic trends: Electronegativity, atomic radii
 Nuclear chemistry: Mass number, atomic number
IV. Molecular Structure
 Modes of bonding: ionic, covalent (both polar and non-polar)
 Lewis Dot, VSEPR, polarity, bond angles, resonance structures
V. Solutions
 Molarity: mol solute/L solution; also dilution (M1V1=M2V2)
 Net ionic equations
 Percent dissociation in water (electrolyte strength)
 Molality: mol solute/kg solvent
 Freezing point depression/boiling point elevation ΔTf=Kfm
VI. Acids, Bases and Ionic Equilibria
 Know the “spectator” ions in acid/base reaction: Na+, K+, Cl-, NO3- etc.
 Know general reactions for acid base (strong acid+ strong base, SA + WB, WA+SB)
 Equivalence point, finding unknown concentrations
 Buffers: What makes a buffer, what a buffer is, etc.
 pH: calculate pH of weak acids or reactions prior to the end point (strong acid+ strong
base, SA + WB, WA+SB)
VII. Chemical Equilibrium – Molecular
 General equilibrium expressions: know how to find K
 LeChatlier’s principle: effect of heat upon endothermic/exothermic reactions
 Precipitation reactions
VIII. Kinetics
 Rate of disappearance, rate of formation
 Effect of catalysis
 Rate laws and ahlf life from experimental data
 Energy of activation
IX. Thermodynamics
 Enthalpy, entropy, free energy
 Relation of free energy to equilibrium constant and Eo
I.
X. Electrochemistry
 Calculations of E values for electrochemical cells
 Balancing redox reactions
 Definitions of oxidized and reduced
XI. Descriptive Chemistry
 Nuclear chemistry: Balancing reactions, alpha particles, beta particles, positrons, etc.
 Elemental reactivity: with water, oxygen, acids
 Coordination chemistry: determine coordination number around central metal
 Ionization energy periodic trend
 General nomenclature
X. Laboratory: General familiarity with basic techniques and appearance of common substances