1 . Which of these bonds is the most polar?
a) C – N
b) Br – Cl
c) F - F
d) O – O
e) O - C
2. SCl2, a cherry-red liquid, is the simplest sulfur chloride and one of the most common. Draw
the Lewis structure for SCl2 and apply the VSEPR theory to determine which of the following
statements is correct for this molecule.
4 VSEPR groups
bent geometry
a)
b)
c)
d)
e)
There is one pair of nonbonding electrons on the central atom.
The molecule has a bond angle of about 109.5o.
The molecule is linear.
The molecule has one double bond.
There are several resonance structures for this molecule.
3. Draw the Lewis structure for NCl3 and apply the VSEPR theory to determine which of the
following statements is correct for this molecule.
..
4 VSEPR groups
There are 3 lone pairs on each Cl atom,
which are not shown here.
a)
b)
c)
d)
e)
The molecule has a trigonal pyramidal geometry.
The molecule is nonpolar
The molecule has identical bond angles of 120o.
There are several resonance structures for this molecule.
The central atom contains no lone pairs of electrons.
4. Draw the Lewis structure for CCl4 and apply the VSEPR theory to determine which of the
following statements is correct for this molecule.
The molecule has 4 polar bonds but
due to tetrahedral geometry,
the polarities all cancel.
a)
b)
c)
d)
e)
The molecule has a trigonal pyramidal geometry.
The molecule is nonpolar
The molecule has identical bond angles of 120o.
There are several resonance structures for this molecule.
The molecule is polar
1
5. Balance the following equation. What is the sum of the coefficients of the reactants and
products?
Ag2CO3(s)
2
a) 7
→
4 Ag(s) + _1__ O2(g) +
b) 8
c) 9
d) 10
2
CO2(g)
e) 12
6. Which of the following equations represents an acid-base neutralization reaction?
a) H2SO4 + Zn → ZnSO4 + H2
b) Ba(OH)2 + Na2SO4 → BaSO4 + 2NaOH
c) HCl + AgNO3 → HNO3 + AgCl
d) HNO3 + KOH → KNO3 + H2O acid + base → salt + water
e) WO3 + 3 H2 → W + 3 H2O
7. What is the oxidation number for chlorine in HClO3?
+1 + Cl + 3(-2) = 0
Cl = +5
a) -1
b) -7
c) +1
d) +5
e) +7
8. Identify the oxidizing agent in the following oxidation-reduction reaction.
+2 -2
3 NiO
+
a) Ni2+
0
Al
b) O2-
→
c) Al
+3 -2
Al2O3
0
+ 3 Ni
d) Al3+
Ni2+ accepts electrons from Al
e) Ni
9. A hospital patient is given a solution containing 9.00 x 10-9 g of iodine-131 (isotopic
weight: 131). How many atoms of iodine are present? Avogadro’s Number = 6.02 x 1023
a)
b)
c)
d)
e)
4.14 x 1015
6.68 x 1017
1.36 x 108
1.36 x 109
4.14 x 1013
9.00 x 10-9g x 1 mol x 6.02x1023 atoms
131 g
1 mol
10. In which of the following pairings of masses does the first listed mass contain more moles
of substance than the second listed mass?
a)
b)
c)
d)
e)
18.02 g H2O and 18.02 g NH3
44.01 g CO2 and 44.01 g CO
105 g CH4 and 105 g NO2
more than one correct response
no correct response
calculate molar masses, then moles of each
2
11. In the following reaction, how many grams of H2O are produced if 6.13 g of N2H4 react?
a) 1.72 g
b) 3.45 g
c) 12.3 g
d) 6.89 g
e) 8.96 g
N2H4 + 3O2 → 2NO2 + 2H2O
M.W. = 18.02
M.W. 32.06
6.13 g x 1 mol x 2 mol H2O x 18.02 g
32.06 g 1 mol N2H4 1 mol
12. How many moles of carbon monoxide will be produced from the reaction of 1.5 moles of
SiO2 and 1.5 moles of carbon? (Hint: one reagent is limiting)
a)
b)
c)
d)
e)
0.50
1.0
1.5
2.0
3.0
SiO2
+
1.5 moles
1
3C
→ SiC + 2 CO
1.5 moles
3
limiting reagent has lowest mole to coefficient ratio
1.5 moles C x 2 CO
3C
13. How many moles of oxygen atoms are in 78.45 g of Al2(SO4)3?
F.W. Al2(SO4)3 = 342.14 amu
a)
b)
c)
d)
e)
0.1150
0.2300
0.6879
0.9200
2.752
78.45 g x
1 mol
342.14 g
x
12 moles O
1 mol Al2(SO4)3
14. The mineral zircon contains 49.8% Zr, 15.3% Si and 34.9% O. What is the empirical
formula? (Atomic weights: Zr = 91.2, Si = 28.1, O = 16.00)
a)
b)
c)
d)
e)
ZrSiO2
ZrSiO4
Zr2SiO5
ZrSi2O4
ZrSiO3
49.8 g Zr = 0.55 mol
15.3 g Si = 0.54 mol
34.9 g O = 2.18 mol
0.55/0.54 = 1
0.54/0.54 = 1
2.18/0.54 = 4
15. In which of the following groupings are the three terms closely related?
a) kinetic energy, energy of motion, cohesive forces
b) potential energy, energy of attraction, disruptive forces
c) kinetic energy, electrostatic interactions, disruptive forces
d) kinetic energy, energy of attraction, cohesive forces
e) potential energy, electrostatic interactions, cohesive forces
Each answer (c and e) received full credit.
3
16. Which of the following statements concerning evaporation is INCORRECT?
a) Increasing the temperature of the liquid increases the rate of evaporation.
b) Evaporation causes the liquid temperature to decrease.
c) Increasing the surface area of the liquid decreases the rate of evaporation.
d) Molecules with energies considerably above average are those that escape from the
liquid.
e) Evaporation is an endothermic process.
17. Which conversion of units for pressure is CORRECT? 760 mm Hg/torr = 1 atm
a)
b)
c)
d)
e)
1.14 x 103 mm Hg = 1.50 atm
228 mm Hg = 0.351 atm
152 torr = 0.217 atm
0.0600 atm = 45.6 cm Hg
530 torr = 530 cm Hg
18. Which of the following is NOT an indicator of STRONG intermolecular forces in liquids?
a) High Vapor Pressure
Low Vapor Pressure is an indication of Strong forces.
b) High Heat of Vaporization
c) High Viscosity
d) High Surface Tension
e) None of the above.
19. The pressure on a 14.4 L sample of oxygen at 748 mm Hg is increased to 1.31 x 103 mm Hg
at constant temperature. What will be the new volume in L?
a)
b)
c)
d)
e)
25.2
17.5
12.4
8.22
6.30
VP = VP
14.4 L x 748 mm Hg = V x 1.31 x 103 mm Hg
20. Gas evolved in the fermentation of sugar in wine making occupies a volume of 0.75 L at
20oC at 720 mm Hg. What volume (L) would the gas occupy at 39oC and 1.00 atm?
a)
b)
c)
d)
e)
0.80
0.73
0.76
0.67
0.85
VP/T = VP/T
0.75 L x 720 mm Hg =
(20 + 273) K
4
V x 760 mm Hg
(39 + 273) K
21. What is the density of neon in g/L at STP?
a)
b)
c)
d)
e)
0.90
0.45
1.8
11.2
18.2
Ne = 20.18 amu = 1 mol
1 mol = 22.4 L at STP
density = mass/volume
= 20.18 g/22.4 L
22. In which of the following molecules will hydrogen-bonding be the strongest?
a)
b)
c)
d)
e)
CH4
NH3
H2Se
H2
CH3CH2OH
no H-bonding
weaker H-bonding, a gas at RT
no H-bonding
no H-bonding
stronger H-bonding to O than to N
23. Assume 453.6 g of dry ice (solid CO2) is placed in an evacuated 50.0 L closed tank. What
will be the pressure in the tank in atmospheres at a temperature of 45oC? Assume that all
the CO2 has been converted into gas. M.W. CO2 = 44.01; the universal gas constant is
0.0821 L atm mole-1 K-1
n = 453.6 g x 1 mol/44.01 g = 10.31 mol
a) 7.25
b) 6.10
P x V = nRT
c) 10.8
P x 50 L = 10.31 mol x 0.0821 L atm mole-1 K-1 x (45 + 273)K
d) 5.38
e) 9.15
24. Which of the following is NOT a characteristic of a solution?
a)
b)
c)
d)
e)
It is a homogeneous mixture.
It is composed of one solvent plus one or more solutes.
Solvent and solute can be separated by filtration.
One visible phase.
Composition can vary.
25. Which of the following statements is NOT correct?
a) Most solids become more soluble in water with increasing temperature.
b) The solubility of a gas in water decreases with increasing temperature.
c) The solubility of a gas in water increases with increasing pressure.
d) A concentrated solution contains the maximum amount of solute that can be
dissolved under a given set of conditions. (correct: A concentrated solution contains
a large amount of solute relative to the amount that could dissolve. The maximum
amount is contained in a saturated solution.)
e) When salts dissolve in water, disorder/entropy increases.
5
26. When an aqueous solution of potassium sulfate is mixed with an aqueous solution of barium
chloride a precipitate is formed. Consult the solubility rules below and identify the
spectator ions for this reaction?
BaSO4 (s) is insoluble, precipitation drives the reaction.
a) K+ and ClK+ and Cl- are soluble and do not react = spectator ions
2+
b) Ba and Cl
c) K+ and SO42d) Ba2+ and SO42e) none are spectator ions
27. Which of the following binary molecules is named INCORRECTLY?
a)
b)
c)
d)
e)
H2O2 hydrogenperoxide
S2Cl2 disulfur dichloride
CCl4 carbon tetrachloride
C2H6 ethane
P4O10 phosphorus decoxide (tetraphosphorus decoxide)
28. Which of the following setups is correct to calculate the number of grams of CO required to
produce 3.2 moles of iron according to the following equation?
(Atomic weights: Fe = 55.85, C = 12.01, O = 16.00)
Fe2O3 + 3 CO → 2 Fe + 3 CO2
a) 3.2 moles Fe x
2 moles Fe
3 moles CO
x
28 g CO
1 mole CO
b) 3.2 moles Fe x
3 moles CO
2 moles Fe
x
28 g CO
1 mole CO
c) 3.2 moles Fe x 3 moles CO
2 moles Fe
x
1 mole CO
28 g CO
d) 3.2 moles Fe x 2 moles Fe
3 moles CO
x
1 mole CO
28 g CO
6
29. To three significant figures, what is the percent of sulfate ions, SO42-, in Al2(SO4)3?
(Atomic weights: Al = 26.98, O = 16.00, S = 32.07) F.W. Al2(SO4)3 = 342.17 amu
F.W. SO42- = 96.07 amu
a) 28.1
b) 84.2
3 x 96.07 amu x 100
c) 56.1
342.17 amu
d) 65.7
e) 36.3
30. To avoid nitrogen narcosis and oxygen toxicity, special gas mixtures are breathed by
researchers and navy personnel at great depths in the ocean. For example, a 2 % oxygen
and 98 % helium mixture may be selected for work at 300 ft, where the total pressure is
10 atm. What is the partial pressure of oxygen at this depth?
a)
b)
c)
d)
e)
8 atm
2 atm
0.2 atm = 10 atm x 0.02 O2
0.8 atm
9.8 atm
7