941_2nd Exam_941117
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) If the heat capacity of a ceramic cup is 0.820 J °C-1 , how much heat is required to raise the temperature of the
cup from 25.0° C to 50.0°C?
A) 41.0 J
B) 50.0 J
C) 61.0 J
D) 82.0 J
E) 20.5 J
Answer: E
2) Which of the following is an example of an object possessing potential energy?
A) a rock on a beach
B) a snake in the grass
C) a penny on the floor
D) a boulder in a valley
E) a bird perched in a tree
Answer: E
3) A sample of neon gas has a volume of 2.50 L at 780. torr and 24°C. How many neon atoms are in the sample?
A) 5.72 × 1024
B) 6.32 × 1022
C) 4.81 × 1025
D) 6.02 × 1023
E) none of the above
Answer: B
4) A mixture of three gases (N2 , Ar, and O2) at 2.6 atm is found to contain 28% N2 and 1.0% Ar. What is the partial
pressure of O2?
A) 1.8
B) 1.9
C) 180
D) 0.75y
E) 0.71
Answer: A
5) The ratio of the mass of oxygen that combines with 1.0 g of hydrogen in water to the mass of oxygen that
combines with 1.0 g of hydrogen in hydrogen peroxide is 1:2. Taken by itself, this fact demonstrates what
natural law?
A) The Atomic Theory
B) Periodicity
C) Constant Composition
D) Conservation of Mass
E) Multiple proportions
Answer: E
6) Through which of the following does diffusion occur fastest?
A) a solution
B) a solid
C) a liquid
D) a gas
E) The rate of diffusion is not dependent upon the phase of a substance.
Answer: D
1
7) Acetylene gas, C2 H2 , can be produced by the reaction of calcium carbide and water.
CaC2 (s) + 2 H2 O (l)
C2 H2 (g) + Ca(OH)2 (aq)
How many liters of acetylene at 742 mm Hg and 26°C can be produced from 2.54 g CaC2 (s)?
A) 0.315 L
B) 0.0870 L
C) 3.37 × 10-4 L
D) 0.0156 L
E) 1.00 L
Answer: E
8) How much heat, in kJ, is required to raise the temperature of 125 g H2O from 24.3°C to 64.9°C? The specific
heat of water is 4.18 J g-1 °C-1 .
A) 523 kJ
B) 21.2 kJ
C) 42.4 kJ
D) 12.7 kJ
E) 33.9 kJ
Answer: B
9) Which of the pairs of substances would produce a precipitate when equal volumes of 0.5 M aqueous solutions
of each are mixed?
A) NaOH and HCl
B) BaCl2 and KNO3
C) (NH4 )2 CO3 and K2SO4
D) AgNO3 and NaCl
E) Pb(NO3)2 and NaNO3
Answer: D
10) When heat is absorbed by the system from the surroundings, the process is said to be __________, and the sign
of process is __________.
A) endothermic; positive
B) spontaneous; positive
C) exothermic; negative
D) endothermic; negative
E) exothermic; positive
Answer: A
11) The net ionic equation that describes what happens when solutions of Ba(OH)2 and NaNO3 are mixed is:
A) Na+ (aq) + OH- (aq)
B) Na+ (aq) + NO3- (aq)
C) Ba2+ (aq) + 2 OH- (aq)
D) Ba2 + (aq) + 2 NO3- (aq)
E) none of the above
NaOH (s)
NaNO 3 (s)
Ba(OH)2 (s)
Ba(NO3)2 (s)
Answer: E
12) What is the oxidation number of chromium in Cr2 O7 -2?
A) +3
B) -3
C) +6
Answer: C
2
D) +4
E) +2
13) Respiratory therapists use the unit "cm of H2 O" to measure small differences in pressure. The density of
mercury is 13.6 g/cm3 , and the density of water is 1.00 g/cm3. A pressure of 100 mm Hg is how many cm of
H2 O?
A) 7.35
B) 1360
C) 136
D) 1.00
E) 13.6
Answer: C
14) It took 49 sec for 1.0 L of helium to effuse through a pin hole. How long will it take for 1.0 L of methane, CH4 , to
effuse under identical conditions?
A) 12 s
B) 196 s
C) 7 s
D) 98 s
E) 25 s
D) -1
E) 0
Answer: D
15) What is the oxidation number of oxygen in Na2 O2 ?
A) -2
B) +2
C) +1
Answer: D
16) Consider 0.1 M solutions of the following substances. Which would have the greatest electrical conductivity?
A) CH3COOH
B) HCl
C) NH4 Br
D) Ca(OH)2
E) CH3NH2
Answer: D
17) In which of the compounds shown below is the sulfur most oxidized?
A) H2 S
B) S2 Cl2
C) Na2 SO4
D) NaSO3
E) S8
Answer: C
18) What mass of oxygen gas, measured at STP, is required in order to release 9250 kJ of heat to the surroundings?
A) 339
CH4 + 2 O2
B) 665
CO2 + 2 H2O
C) 51.2
H = -890.3 kJ
D) 1330
Answer: B
19) When the following reaction is balanced under acidic conditions, the coefficient of water is:
Mn2+ (aq) + MnO4 - (aq)
A) 1 on left
B) 2 on left
C) 0, H2O doesn't appear in the balanced equation.
D) 1 on right
E) 2 on right
Answer: B
3
MnO2 (s)
E) 397
20) Use the following thermochemical equations
C2 H2 (g) + 5/2 O2 (g)
C2 H6 (g) + 7/2 O2 (g)
2 CO2 (g) + H2 O (g)
2 CO2 (g) + 3 H2 O (g)
H2 (g) + 1/2 O2 (g)
H2 O (l)
H° = -1300 kJ
H° = -1560 kJ
H° = -286 kJ
to calculate H° for the following reaction:
C2H2 (g) + 2 H2 (g)
A) -2860 kJ
B) -3146 kJ
C2 H6 (g)
C) -312 kJ
D) +1560 kJ
E) -16 kJ
Answer: C
21) According to the kinetic molecular theory, kinetic energy is conserved in a collision. We say that these collisions
are
A) rubbery.
B) unfavorable.
C) soft.
D) hard.
E) elastic.
Answer: E
22) What is the difference between extensive and intensive properties?
A) Extensive properties depend on the kinetic energy of a system, while intensive properties depend on the
potential energy.
B) Extensive properties depend on the quantity of matter, while intensive properties do not.
C) Extensive properties include color and smell, while intensive properties include enthalpy and mass.
D) Extensive properties occur outside a system, while intensive properties occur inside.
E) Extensive properties are state functions, while intensive properties are not.
Answer: B
23) Calculate the density of ammonia gas, NH3 , at 24°C and 738 torr.
A) 0.679 g L-1
B) 1.48 g L-1
C) 514 g L-1
D) 8.38 g L-1
E) 0.836 g L-1
Answer: A
24) Which is correct regarding an endothermic reaction?
A) The reaction does not occur.
B) The enthalpy of the reactants is higher than the enthalpy of the products.
C) The reaction liberates heat.
D) The temperature increases when the reaction is carried out in a calorimeter.
E) The sign of the H is positive.
Answer: E
25) A 55.6 g pool of mercury initially at 28.0°C absorbs 407 J of heat. What is the final temperature of the mercury?
The specific heat of mercury is 0.139 J g-1°C-1 .
A) -24.7°C
B) 52.7°C
C) 80.7°C
D) 91.9°C
E) 24.7°C
C) Ga
D) Sb
E) In
Answer: C
26) Which of the following is a metalloid?
A) Sn
B) S
Answer: D
4
27) What is the coefficient of CH3 OH after balancing the following equation?
CH3OH + CrO42A) 3
B) 0
HCOO- + Cr2O3
C) 4
D) 1
E) 2
Answer: A
28) A volume of 50.0 mL of 0.400 M HBr at 24.35° C is added to 50.0 mL of 0.400 NaOH, also at 24.35°C. The final
temperature is 27.06°C. Calculate the enthalpy change, H, in kJ, for the reaction:
HBr (aq) + NaOH (aq)
A) 27.4
B) 12.8
NaBr (aq) + H2O (l)
C) 42.8
D) 56.7
E) 140
Answer: D
29) Which of the following species is not a base in water?
A) CH3NH2
B) CH3OH
C) NH2
D) NaOH
E) All of the above are bases in water.
Answer: B
30) If a weather report gives the atmospheric pressure as 95.5 kPa, what is the pressure in torr?
(101.325 kPa = 760 torr)
A) 0.716
B) 716
C) 0.806
D) 806
E) 0.942
Answer: B
31) Given the thermochemical equation:
2 NO (g) + O2 (g)
2 NO2 (g)
calculate H° for the following reaction:
NO2 (g)
A) +57.0 kJ
B) +114.0 kJ
NO( g) +
H° = -114.0 kJ
1
O (g)
2 2
C) -114 kJ
Answer: A
32) Which statement is not correct?
A) Heat and work are state functions.
B) The enthalpy change is the heat of reaction at constant pressure.
C) Enthalpy is a state function.
D) Internal energy, E, is a state function.
E) Heat is given off to the surroundings in an exothermic reaction.
Answer: A
5
D) -57.0 kJ
E) +128 kJ
33) Which of the following is NOT a component of internal energy?
A) vibrations
B) rotations
C) reactivity
D) translations
E) intermolecular forces
Answer: C
234) How many liters of a 3.85 M solution of Fe2+ are needed to titrate 250.0 mL of a 0.125 M CrO 4 solution?
H+ + CrO42- + Fe2+
A) 0.0487
B) 8.12
Fe3+ + Cr2O3 + H2 O
C) 0.0244
(not balanced)
D) 4.87
E) 4.06
Answer: C
35) Which of the following is a restatement of Charles' Law (where "a" represents a constant)?
A) P/V = a
B) PV = T
C) PT = a
D) PV = a
E) V/T = a
Answer: E
36) Which of the following substances is a weak electrolyte in aqueous solution?
A) CH3COOH
B) NH4 NO3
C) HNO3
D) HCl
E) NaOH
Answer: A
37) What is the heat capacity of a metal slug if a temperature rise from 25°C to 54°C requires 135 J?
A) -4.6 J/°C
B) 4.7 J/°C
C) 0.60 J/°C
D) 2.5 J/°C
E) 0.21 J/°C
Answer: B
38) Which of the following has the highest total concentration of ions?
A) 0.05 M HBr
B) 0.1 M NaCl
C) 0.04 M (NH4 )2 SO4
D) 0.03 M Al2(SO4 )3
E) 0.1 M CH3 OH
Answer: B
39) The assumptions of the kinetic-molecular theory are most likely to be correct under what conditions?
A) low temperature-high pressure
B) high temperature-high pressure
C) high temperature-low pressure
D) low temperature-low pressure
E) always correct
Answer: C
40) How much kinetic energy does a 2.0 kg mass have if it is moving 2.0 m/s?
A) 12 J
B) 8.0 J
C) 4.0 J
D) 1.0 J
Answer: C
6
E) 2.0 J
41) What volume, in mL, of 0.750 M HCl would be required to neutralize a 1.50 g sample of Ca(OH)2 ?
A) 26.7
B) 35.0
C) 54.0
D) 53.5
E) 2.00
Answer: C
42) What mass of CH4 (g) must be burned to release 334 kJ of heat to the surroundings?
A) 6.00 g
CH4 (g) + 2 O2 (g)
CO2 (g) + 2 H2 O (l)
B) 0.426 g
C) 55.6 g
H° = -890 kJ
D) 2.66 g
E) 0.375 g
Answer: A
43) A sample of helium in a balloon at 24°C has a volume of 1.45 L. What will be the volume at 87°C in L?
A) 5.26
B) 1.76
C) 0.995
D) 2.11
E) 0.40
Answer: B
44) Which of the following is a spectator ion in the reaction between NaOH and HCl?
A) Na+
B) K+
C) H2 O
D) OH-
E) H+
Answer: A
45) Consider four identical 1.0-L flasks containing the following gases each at 0°C and 1 atm pressure. Which
sample has the most molecules?
A) SO2
B) H2
C) NH3
D) O2
E) same for all gases
Answer: E
46) A balloon of helium whose volume is 2.20 L at 25°C is cooled by pouring liquid N2 over it. The final
temperature of the balloon is -196°C. What is the final volume, in L?
A) 8.5
B) 0.57
C) -17
D) 2.2
E) 0.28
Answer: B
47) Which of the following compounds would most likely not be found in gasoline?
A) C6 H12O6
B) C7 H8
C) C5 H12
D) C2 H6 O
E) C6 H14
Answer: A
48) What is the kinetic energy of a ball whose mass is 1.1 kilograms and whose velocity is 5.0 m/s?
A) 2.8
B) 14
C) 11
D) 15
E) 28
Answer: B
49) Five 22.4 L containers each hold a different gas at STP. The container holding which gas would have the
greatest mass, in grams?
A) O2
B) CO2
C) He
D) N2
E) H2
Answer: B
7
50) Calculate the number of atoms in 48.0 g glucose, C6 H12O6 .
A) 1.60 × 1023
B) 2.26 × 1022
C) 1.64 × 1016
Answer: D
8
D) 3.85 × 1024
E) 9.24 × 1025