1 C
2 E
3 B
4 A
5 C
6 D
7 C
8 E
9 B
10 E
11 D
12 D
13 C
14 C
15 E
16 D
17 E
18 D
19 C
20 D
21 C
22 D
23 C
24 E
25 D
26 B
27 A
28 D
29 A
30 B
31 D
32 E
33 A
34 C
35 C
36 A
1st Practice Multiple Choice Answers
Hunds rule maximizes unpaired electrons  paramagnetic.
Diffraction is a wave phenomena (I'll explain next year).
Pauli exclusion principle requires each electron to have unique
set of 4 quantum numbers  2 per orbital.
Heisenberg uncertainty principle limits what we know about the
position of a moving object.
The triple covalent bond between N has the greatest bond
energy  requires the most energy to "dissociate".
O2 contains a double bond  bond order = 2.
1  + 2  bonds = triple bond  NN.
sp3d2 hybrid has six electron pairs around the central atom,
which form an octahedron.
mol H+ = mol OH- = 0.032 L x 0.50 M = .016 mol
0.016 mol/0.020 L = 0.80 M
Mn in MnO4- goes from +7 oxidation # to +4  is reduced, which
makes it the oxidizing agent.
6 Ag+ + 6 e-  6 Ag
AsH3 + 3 H2O + 6 OH-  H3AsO3 + 6 H+ + 6 e- + 6 OHBecause of high mass  has a relatively low velocity and 
lower penetration than  .
P1V1/T1 = P2V2/T2  0.80/400 = V2/300  V2 = 0.60 atm
Boiling point only depends on partial pressure of H2O, which is
changed by elevation.
Molarity is moles solute/volume solution. To calculate moles
solute, you need molar mass (mol = m/MM). To calculate
volume of solution you need density (V = m/d).
CH3CH2OH has –OH, which forms strong H-bonds  higher
boiling point.
Solubility increases with increasing polarity. X has no polar
regions, Y has one –OH, and Z has two –OH,  X < Y < Z.
MM = mRT/PV = (3.0)(0.08)(400)/(1.0)(1.5)
Ptot = PO2 + PH2O  161 mm Hg = PO2 + 28 mm Hg
 PO2 = 133 mm Hg
d = m/V = (25.0 – 3.0)/11.0 = 2.00 g/cm3 (3 s.f.)
Speed decreases when temperature decreases. (Spacing of the
molecules depends on the container volume)
HF is a weak acid only partially ionizes.
nH+MH+VH+ = NOH-MOH-VOH(1)(0.150)VH+ = (2)(0.120)(25.0)  VH+ = 40.0 mL
87 g x 1 mo/174 g = 0.5 mole K2SO4
0.5 mol/0.250 L = 2 M K2SO4 4 M K+ and 2 M SO42-.
Atomic trends: Ionization energy and electronegativity
decrease and atomic radius increases down a family.
Standard Potentials: Fluorine is at the top.
Halogen listed higher will take electron from halogen listed
lower (greater electron affinity) this is one is false.
SO2 + 2 KOH  K2SO4 + H2O
1,000 L x 0.25 mol KOH x 1 mol SO2 x 64 g SO2 = 8 kg
1L
2 mol KOH
1 mol
BCl3 has no lone electron pairs around B  trigonal planar
CHCl3 is tetrahedron, NCl3 is trigonal pyramidal.
0.44 g CO2 x 1 mol CO2 x 1 mol CaCO3 x 100 g = 1 g
44 g
1 mol CO2
1 mol
1 g CaCO3/1.25 g sample = 0.80
H2S has 2 unshared pairs, NH3 has 1 unshared pair, CH4, HCN
and CO2 have no unshared pairs.
16 hr x 3600 s x 3 C x 1 mol e- x 1 mol Cu x 63.55 g =
1 hr
1 s 96,500 C 2 mol e- 1 mol Cu
ra/rb = (MMb/MMa)½  2/1 = (MMb/17)½  MMb = 68 (Cl2)
differing polarities allow molecules X and Y to be preferentially
attracted to the mobile or stationary phase in column
chromotography
Zero dipole moment is non-polar. Benzene ring is symmetrical,
SO2, NH3 and H2S are non-symmetrical and NO has different
electronegativities on opposite sides.
Final rinse should be with the titrant so that the first few drops
aren't diluted.
O2 + 4 H+ + 4 e-  2 H2O
4(Fe(OH)2 + OH-  Fe(OH)3 + 1 e-)
4 Fe(OH)2 + O2 + 2 H2O  4 Fe(OH)3
MM = mass acid/moles of NaOH. If some of the acid wasn't
transferred, then it would have taken less volume of NaOH to
reach equivalence. Calculated moles NaOH (M x V) would be
37 B
38 C
39 E
40 D
41 A
42 C
43 E
44 A
45 B
46 D
47 C
48 E
49 B
50 C
51 B
52 D
53 D
54 C
55 A
56 C
57 C
58 D
59 C
60 C
61 B
62 E
63 D
64 E
65 B
66 D
67 A
68 A
69 C
70 C
71 A
72 A
less calculated MM would be too large.
+ electrode = anode: 2 I-  I2 + 2 e- (amber color)
- electrode = cathode: 2 H2O + 2 e-  H2 + 2 OH- (gas)
Ionization energy converts a gas atom into a cation.
Lattice energy measures the strength of an ionic bond.
Unreactive atoms have complete s and p sublevels.
An excited state occurs when a lower energy state is left
unfilled.
Valence electrons include s and p electrons.
Transition metals contain d electrons.
Lattice of positive and negative ions describes an ionic
compound, which is composed of metal and nonmetal ions.
Lattice with delocalized electrons describes a metal.
CO2 is a non-polar molecule, where the C=O bond is a double
covalent bond, with weak dispersion forces holding
neighboring molecules together.
CH4 is a non-polar molecule, where C–H bond is a single
covalent bond, with weak dispersion forces holding
neighboring molecules together.
Fluorine along with nitrogen, oxygen and the noble gases are
the elemental gas.
There is .1 mol of Au in .05 mol Au2S3, 0.1 x 197 = 19.7 g.
C10H12O4S + 12 O2  10 CO2 + SO2 + 6 H2O
Lattice energy, E  Q1Q2/d, where Q1 and Q2 are the ion charges
and d is the distance between ions.Mg2+ and O2- have greater
charge, but O2- is larger than F-.
Se goes from -2 in H2Se to +6 in SeF6.
O goes from -1 in O2F2 to 0 in O2.
| | |
–C3–C2=C1– Carbon 1 and 2 are sp2 and carbon 3 is sp3
|
There is 0.1 mol Cl- in 0.1 mol NaCl and 0.2 mol of Cl- in 0.1 mol
of CaCl2, which add up to 0.3 mol Cl-. It takes one mol Ag to
react with each mol of Cl-  0.3 mol Ag+ are needed.
The half-reaction is reduction (electrons on the reactant side)
and reduction takes place at the cathode.
15 min x 60 s x 10 C x 1 mol e- x 1 mol Al x 27 g Al =
1 min 1 s 96,500 C 3 mol e- 1 mol Al
The big gap in ionization energy occurs after the third electron
is removed, which means there are 3 valence electrons, Al.
The largest dipole moment describes the most polar molecule,
which would be the one with the greatest electronegativity
difference between atoms (farthest apart on the periodic table).
Speed is related to temperature: v = (3RT/M)½, if the
temperature is constant then so is the average speed.
62.2 g/178  1/3 moles Hf, 37.4 g/35.5  1 mol Cl  HfCl3
It takes three ½-life to lose 87.5 % (7/8 of the total).
3 T½ = 24 days  T½ = 8 days.
Evaporating the water will leave the solid behind.
Going from left to right on the periodic table, the number of
protons in the nucleus increase, but the number of core
electrons remain constant. The increased effective charge of
the nucleus pulls the valence electrons in closer resulting in
reduced radii.
Rutherford bombarded gold foil with alpha particles. The small
but significant number of alpha particles that were reflected by
the gold foil indicated a small, dense positively charged
nucleus in the center of each atom.
Gases are most soluble under high partial pressure and low
temperature.
2.5 mol I2 x 10 mol HI/5 mol I2 = 5 mol HI
Only a positive ion would react with NaI, since Na doesn't form
ppt with anything. PbI2 is insoluble (and is yellow).
Eocell = Eored + Eoox
Eoox = Eocell – Eored = 2.46 V – 0.80 V = 1.66 V
Eored = -Eoox = -1.66 V
Boiling occurs when the water vapor pressure equals
atmospheric pressure, which is less at higher elevations, 
water boils at a lower temperature at high elevations.
[OH-] = (0.040 L)(0.25 M) + (0.060 L)(0.30 M) = 0.28 M
0.100 L
0.03 mol NH4NO3 decomposes to form 0.09 mol gas.
P = nRT/V = (0.09)(0.08)(400)/(1) = 2.8 atm
Rate of effusion depends on molar mass, where lighter gases
effuse faster,  PHe < PNe < PAr.
73 D
74 C
75 A
76 A
77 B
78 A
79 C
80 D
81 B
82 E
83 D
84 B
85 A
86 D
87 C
88 B
89 B
90 A
91 A
92 E
93 C
94 B
95 E
96 C
97 A
98 B
99 D
100 E
101 B
102 B
103 B
104 B
105 D
106 A
107 A
108 B
109 C
110 B
Diamonds are covalently bonded throughout,  separating C
atoms requires the breaking of covalent bonds.
0.1 L x 0.1 M = 0.01 mol Ba2+, 0.1 L x 0.05 M = 0.005 mol SO42-.
All SO42- reacts with 0.005 mol Ba2+ leaving 0.05 mol Ba2+ in 0.2
L = 0.025 M
Gas that are polar with high molecular mass deviate the most
from ideal behavior.
Initial ions: 0.3 mol Na+, 0.1 mol PO43-, 0.1 mol Ag+ and 0.1 mol
NO3-. All Ag+ and 0.03 mol PO43- react to form ppt, [PO43-] <
[NO3-] < [Na+].
Only Pb2+ is insoluble in Cl-.
Sulfur has 4 p electrons ()()(), two of which are unpaired.
Ga is in column 13, which has one p electron.
CH2=CH2. CO2 has two double bonds, and H2O and PH3 have
only single bonds.
H2O and PH3 are the only polar molecules. H2O has a greater
electronegativity difference.
PH3 has a pair of electrons around P, which pushes the H's
down forming a trigonal pyramidal shape.
v = (3RT/MM)½  the gas with a molar mass closest to 28 would
have the same velocity.
The volumes are the same for all gases, so the one with the
greatest MM would be most dense.
Rate  v = (3RT/MM)½  the gas with the smallest MM would
have the greatest rate.
A precipitation reactions are:
cation + anion  insoluble ionic compound.
One element shows up in two products with different oxidation
states.
Combustion is a general term for redox reaction where oxygen
gas is reduced.
Freezing occurs at the lower plateau (boiling occurs at the
higher plateau.
Boiling is occurring during second plateau, where liquid
molecules are entering the gas phase.
Isoelectric series includes elements that are within three
squares of a noble gas.
SO2(g) is 1/5 the total moles  1/5 the total pressure
(800/5 = 160 mm Hg).
The mole ratio in the compound is 2 K + 1 Te + 3 O the
formula is K2TeO3.
0.250 L x 0.10 mol/L x 250 g/mol = 6.25 g
Most ionic compounds are composed of a metal cation and a
non-metal anion.
Diamonds are covalent network solids where carbon atoms are
bonded covalently to each other.
At common temperature and pressure, moles of gas are
directly proportional to liters  4 L CO2 = 12 L O2.
KNO3 has the greatest change in solubility between 90oC and
30oC  a higher % precipitates at lower T.
63.55 = 63(1 – x) + 65(x) = 63 – 63x + 65x = 63 + 2x
0.55 = 2x  x  0.25
Atomic radius decreases because each element in a period
gains a proton w/o increasing core electrons.
The effective nuclear charge for Na is lower, which results in a
weaker attraction for valence electrons.
Ionic compounds are soluble in polar solvents. CCl4 is
nonpolar.
NO3-: N + 3(-2) = -1  N = +5
NO: N + (-2) = 0  N = +2
C3H8 + 5 O2  3 CO2 + 4 H2O
Unshared pairs of electrons take up more space, which leaves
less space for H and a tighter angle.
Higher boiling pt. is due to stronger intermolecular bonds—
dispersion forces, which increase with MM.
.02 L x .2 mol MnO4-/L x 3 mol ClO2-/4 mol MnO4- = 0.0030
Phase change involves intermolecular bonds, which are Hbonds for water.
SiO2 is covalent network, which contains covalent bonds
throughout. The others are all molecular.
.200 F x 1 mol e-/1 F x 1 mol Ni2+/2 mol e- x 58.7 g/mol = 5.87 g
When base from the buret reacts with all the acid in the flask,
111 C the contents of the flask turn from clear to pink due to the
phenolphthalein.
112 D 35.75 mL - 12.55 mL = 23.20 mL
Atomic radius decreases from left to right and increases from
113 C top to bottom. Cations are smaller than their neutral atom and
anions are larger than their neutral atom.
Elements in the same family (column) have similar chemical
114 E
properties.
Processes that involve breaking bonds (moving molecules
115 C
apart) are endothermic.
116 D At the same temperature, small molecules move faster.
H3C- has 4 atoms attached to C  sp3; -C- has 2 atoms attached
117 C
to C  sp; -CH has 2 atoms attached to C  sp.
ave. mass= [(0.1 x 30amu) + (0.7 x 32 amu) + ( 0.2 x 33 amu)]
118 C
119 E
120 C