# Chem: Equilibrium Constant and Molar Heat Capacity

Topics: Equilibrium constant, Chemical reaction, Chemical kinetics Pages: 8 (2256 words) Published: December 12, 2012
CHEM 1332
SPRING 2008 – (NEW) FINAL

1.How much energy is needed to convert 180 grams of ice at -10 ºC to liquid water at 10 ºC? (The molar heat capacity of liquid water is 75.4 J/mol ºC; the molar heat capacity of ice is 40.2 J/mol ºC. The molar heat of vaporization of water is 40.7 kJ/mol. The molar heat of fusion of water is 6.02 kJ/mol.)

(A)71.8 kJ(B)419 kJ(C)64.2 kJ(D)64.6 kJ(E)11,620 J

2.Which physical property of a liquid is NOT the result of strong intermolecular forces?

(A)high vapor pressure(B)high boiling point(C)high heat of fusion (D)high melting point(E)high heat of vaporization

3.Which of the following statements is TRUE?

(A)Most gases are more soluble in liquids at higher temperatures. (B)In any solution, the solvent has to be liquid.
(C)The solubility of a gas in a liquid is inversely proportional to the pressure. (D)If the heat of solution is negative for a solid in a liquid, then more solid will dissolve at lower temperatures. (E)All of these statements are false.

4.Commercial concentrated sulfuric acid is 98.0 % by mass H2SO4 and has a density of 1.84 g/mL. Calculate the molarity of concentrated sulfuric acid.

(A)0.184 M(B)9.20 M(C)10.0 M(D)15.6 M(E)18.4 M

5.The activation energy of a reaction is 37.6 kJ/mol and the rate constant is 5.4 x 10-3 s-1 at 45°C. What is the rate constant at 145°C?

(A)0.16(B)5.4 x 10-3(C)8.4 x 10-3(D)0.38(E)0.56

6.Which of the following statements is correct for the reaction 2H2 + O2 → 2H2O(g)?

(A)The rate of O2 disappearance is twice the rate of the H2 disappearance. (B)The rate of H2 disappearance is twice the rate of the O2 disappearance. (C)The rate of H2 disappearance is equal to the rate of the H2O disappearance. (D)The rate of O2 appearance is equal to the rate of the H2 disappearance. (E)The rate of H2 disappearance is equal to the rate of the O2 disappearance.

7.The following data were obtained for the reaction 2A → products.

time (min)[A]time (min)[A]time (min)[A]

01.20 1.11.00 2.30.80
4.00.60 5.10.50 6.30.40
8.00.30 10.30.20

What is the order of the reaction and why?

(A)First because there is only one reactant species.(B)Second because the coefficient of A is 2. (C)Zero because of the shape of the plot of [A] vs t.(D)First because the half-life remains constant. (E)Second because the reaction rate decreases with time.

8.Given the initial rate data below for the reaction A(g) + B(g) → C(g) + D(g), what would the initial rate (in M/s) be if [A] = 0.10 M and [B] = 0.30 M?

[A] (M)[B] (M)Rate (M/s)

0.200.102.2 x 10-3
0.400.104.4 x 10-3
0.200.208.8 x 10-3

(A) 3.3 x 10-3(B) 1.7 x 10-3(C) 1.4 x 107(D) 9.9 x 10-3(E) 3.3 x 10-2

9.Which of the mechanisms is most likely, given the observed experimental rate law?

Reaction is:HBr + CH3CH=CH2 → CH3CHBrCH3
Rate Law:rate = k[HBr]3[CH3CH=CH2]

(A)HBr + HBr → H + HBr2(fast)
H + CH3CH=CH2 → CH3CHCH3(slow)
CH3CHCH3 + HBr2 → CH3CHBrCH3 + HBr(fast)

(B)HBr + HBr → H2Br2(fast)
HBr + CH3CH=CH2 → CH3CHBrCH3(fast)
CH3CHBrCH3 + H2Br2 → CH3CHBrCH3 + 2 HBr(slow)

(C)HBr + CH3CH=CH2 → H +CH3CHBrCH2(fast)
H + HBr → H2Br(fast)
CH3CHBrCH2 + H2Br → CH3CHBrCH3 + HBr(slow)

(D)3 HBr + CH3CH=CH2 → CH3CHBrCH3 + H + HBr2(slow)
H + HBr2 → 2 HBr(fast)

(E)Both (B) and (D) are equally likely.

10.Calculate the energy change (in MeV) during the fusion of protium (1H) with deuterium (2H) to make 3He, given the following information:

1H = 1.00794 amu2H = 2.01410 amu3He = 3.10603 amu1 amu = 931.5 MeV

(A)78.2 MeV(B)0 MeV(C)0.00601 MeV(D)2809 MeV(E)6.772 MeV

11.When 232Th decays, it begins a chain reaction that ends at a stable nucleus. Given that the chain goes in the order,...

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