课程名称︰ 普通化学丙
课程性质︰ 物治系 医技系 公卫系 职治系 护理系 药学系 大一必带
课程教师︰ 刘铭璋
开课学院： 理学院
开课系所︰ 化学系
考试日期（年月日）︰ 2014年 1月 8日
考试时限（分钟）： 120 分钟
是否需发放奖励金： 是
（如未明确表示，则不予发放）
试题 :
Final Exam of General Chemistry 1/8/2014
1. At 900°C, Kp =1.04 for the reaction CaCO (s) → CaO(s) + CO (g)
3 ← 2
At a low temperature, dry ice (solid CO ), calcium oxide, and calcium
2
carbonate are introduced into a 50.0-L reaction chamber. The temperature
is raised to 900°C, resulting in the dry ice converting to gaseous CO .
2
For the following mixtures, will the initial amount of calcium oxide
increase, decrease, or remain the same as the system moves toward
equilibrium at 900°C?
Ca: 40.08amu (6%)
a. 655 g CaCO , 95.0 g CaO, P = 0.211 atm
3 CO2
b. 780 g CaCO , 1.00 g CaO, P = 1.04 atm
3 CO2
c. 715 g CaCO , 813 g CaO, P = 2.55 atm
3 CO2
-5
2. At 35°C, K = 1.6 x 10 for the reaction 2NOCl(g) → 2NO(g) + Cl (g)
← 2
In an experiment, 2.0 moles of pure NOCl are placed in a 2.0-L flask.
Calculate the concentrations of all species at equilibrium. (6%)
3. Hydrogen for use in ammonia produced by the reaction
Ni catalyst
CH (g) + H O(g) ──────→ CO(g) + 3H (g)
4 2 ←────── 2
What will happened to a reaction mixture at equilibrium if
a. H O(g) is removed?
2
b. the temperature is decreased (the reaction is endothermic)?
c. an intert gas is added to a rigid reaction container?
d. Ni catalyst is removed?
e. the volume of the container is tripled? (5%)
4. Define enthalpy, entropy, and free energy. What information can be
determined from these thermodynamic functions for a reaction? (10%)
5. For each of the following pairs of substances, which substance has the
smaller value of S°? Give your reason. (6%)
a. C (s) or C (s)
graphite daimond
b. C H OH(l) or C H OH(g)
2 5 2 5
c. N O(g) or He(g)
2
6. Consider the reaction 2POCl (g) → 2PCl3(g) + O (g) (6%)
3 ← 2
a. Calculate ΔG°for this reaction. The ΔG° values for POCl (g) and
f 3
PCl (g) are -502 KJ/mol and -270. KJ/mol, respectively.
3
b. The value of ΔS°for this reaction is 179 J/K‧mol. At what
temperatures is this reaction spontaneous at standard conditions?
Assume that ΔH°and ΔS°do not depend on temperature.
7. Consider the system A(g) → B(g) at 25°C. (6%)
a. Assuming that G°= 8996 J/mol and G°= 11,718 J/mol, calculate the
A B
value of the equilibrium constant for this reaction.
b. Calculate the equilibrium pressures that result if 1.00 mole of A(g) at
1.00 atm and 1.00 mole of B(g) at 1.00 atm are mixed at 25°C.
c. Show by calculations that ΔG = 0 at equilibrium.
8. In each of the following radioactive decay processes, supply the missing
particle. (6%)
8 8
a. Li → Be + ?
3 4
239 235
b. Pu → U + ?
94 92
249 18 263
c. Cf + O → Sg + ?
98 8 106
9. For each pair of isotopes listed, predict which one is less stable and give
your reason: (6%)
6 9 14 12 95 92
(a) Li or Li, (b) C or C, (c) Mo or Tc
3 3 6 6 42 43
10. (a) What kind of nuclear fission reactors are used in Taiwan? (b) Explain
the functions of a moderator and a control rod in a nuclear reactor. (c)
What is the SI unit of dose equivalent (energy dose of the radiation and
its effectiveness in causing biologic damage)? (8%)
11. (a) What is a state function? Is work a state function? (b) State the first
law of thermodynamics. (6%)
12. Calculate the internal energy change for each of the following. (6%)
a. One hundred (100.) joules of work is required to compress a gas. At
the same time, the gas releases 23 J of heat.
b. A piston expands against 1.00 atm of pressure from 11.2 L to 29.1 L. In
the process, 1037 J of heat is absorbed. (1L‧atm = 101.3 J)
13. Consider the following inital rate data for the decomposition of compound
AB to give A and B: (6%)
┌───────┬───────────┐
│[AB] (mole/L)│Inital Rate (mol/L‧s)│
│ 0 │ │
├───────┼───────────┤
│ │ -3 │
│0.200 │3.20 x 10 │
├───────┼───────────┤
│ │ -2 │
│0.400 │1.28 x 10 │
├───────┼───────────┤
│ │ -2 │
│0.600 │2.88 x 10 │
└───────┴───────────┘
a. Determine the rate law and the value of the rate constant.
b. Determine the half-life for the decomposition reaction initally having
1.00 M AB present.
14. One mechanism for the destruction of ozone in the upper atmosphere is
O (g) + NO(g) → NO (g) + O (g) Slow
3 2 2
NO (g) + O(g) → NO(g) + O (g) Fast
2 2
──────────────────────
Overall reaction O (g) + O(g) → 2O
3 2
a. Which species is a catalyst? Give your reason.
b. Which species is an intermediate? Give your reason.
c. Ea for the uncatalyzed reaction O (g) + O(g) → 2O (g)
3 2
is 14.0 kJ. Ea for the same reaction when catalyzed is 11.9 kJ. What is
the ratio of the rate constant for the catalyzed reaction to that for
the uncatalyzed reaction at 25°C? Assume that the frequency factor A
is the same for each reaction. (6%)
15. Radioactive copper-64 decays with a half-life of 12.8 days. (6%)
-1
a. What is the value of k in s ?
64
b. A sample contains 28.0 mg Cu. How many decay events will be produced
64
in the first second? Assume the atomic mass of Cu is 64.0.
64
c. A chemist obtains a fresh sample of Cu and measures its
radioactivity. She then determines that to do an experiment, the
radioactivity cannot fall below 25% of the initial measured value. How
long does she have to do the experiment?
16. Consider the following graph of binding energy per nucleon as a function of
mass number. (8%)
a. What does this graph tell us about the relative half-lives of the
nuclides? Explain your answer.
b. Which nuclide shown is the most thermodynamically stable? Which is the
least thermodynamically stable?
c. What are fusion and fission reactions?
d. What does this graph tell us about which nuclides undergo fusion and
which undergo fission to become more stable? Support your answer.