課程名稱︰普通化學乙下
課程性質︰必修
課程教師︰李弘文
開課學院：理學院
開課系所︰心理系
考試日期（年月日）︰2009.03.25
考試時限（分鐘）：110
是否需發放獎勵金：是
（如未明確表示，則不予發放）
試題 :
I. True/False Section: (20%, 2 pts each)
For a statement to be true, it must be always true.
1.F
Reactions with positive values ofSrΔ轫always become spontaneous at low
temperatures.
2.T
The entropy of vaporization of a substance is always larger than its entropy
of fusion.
3.T
Solutions in which intermolecular forces are stronger in the solution than in
the pure components have negative enthalpies of mixing.
4.F
Consider the reaction F2←→2F Heating the reaction mixture causes the
reaction to shift to the left.
5.T
The solubility of oxygen at a certain temperature is 8 ppm. If the partial
pressure of oxygen is doubled at this temperature, the solubility is 16 ppm.
6.T
The increase in entropy of the system is responsible for the solubilities of
substances that dissolve endothermically.
7.F
ATP hydrolysis liberates chemical energy because O-P bonds are made.
8.T
Bond polarity tends to dominate the trend of acid strengths for binary acids
(ex.H2S and HCl) of elements of the same period.
9.F
In the reaction, SO2(g) + H2O(l)→H2SO3(aq), the Lewis acid is H2O and the
Lewis base is SO2.
10.T
In an ideal binary solution, a solute increases the entropy of the liquid
phase and the enthalpy is left unchanged. Therefore, there is a decrease in
the molar Gibbs free energy of the solvent.
II. Multiple Choice Section: Pick one best answer. (50 %, 2 pts each)
1.C
Which of the following statements is true? A) The molar entropy does not
depend on the structure of the compound. B) The molar entropy of H2O(l) is
about the same as the molar entropy of ice. C) A process that leads to a
decrease in free energy is spontaneous. D) All processes that give positive
changes in energy are spontaneous.
2.D
CalculaterGΔ轫for the decomposition of mercury(II) oxide at 298 K. A) –
117.1 kJ·mol-1 B) +246.2 kJ·mol-1 C) –64.5 kJ·mol-1 D) +117.1 kJ·mol-1
3.A
Water slowly evaporates at 25°C.Which of the following statements regarding
this reaction is true? A) This is a spontaneous reaction that is entropy
driven. B) This is a spontaneous reaction that is enthalpy driven. C) The
signs of the reaction enthalpy and entropy, respectively, are + and +. D) The
signs of the reaction enthalpy and entropy, respectively, are – and –.
4.A
Which of the following graph is correct? S= solid, L=liquid, V=vapor (gas)
A)B) C) D)
5.D
For the reaction HrΔ轫= +198 kJ·mol-1 and SrΔ轫= 190 J·K-1·mol-1 at 298
K. The equilibrium constant for this reaction will be greater than 1 at A)
all temperatures. B) temperatures above 1315 K. C) temperatures below 1300 K.
D) temperatures above 1042 K.
6.A
Iodine sublimes at room temperature. The reaction free
energy/enthalpy/entropy for this reaction, respectively, are A)
negative/positive/positive B) zero/positive/positive C)
zero/positive/negative D) negative/negative/positive
7.B
The enthalpy of hydration of AgBr is (–819 kJ·mol-1) at 25°C. Given that
the hydration enthalpy of Br- is (–309 kJ·mol-1), calculate the enthalpy of
hydration of Ag+ ions. A) –410 kJ·mol-1 B) –510 kJ·mol-1 C) –1128 kJ·
mol-1 D) –309 kJ·mol-1
8.B
For CaCl2, the absolute value of the enthalpy of hydration is larger than the
lattice enthalpy. . This means that for CaCl2 A) the lattice enthalpy is
negative. B) the enthalpy of solution is exothermic. C) the solubility
increases when the temperature increases. D) the enthalpy of hydration is
positive.
9.D
Which of the following statements is true regarding solubility? Assume that
the solute does not affect the solvent and we are dealing with dilute
solutions. A) We can expect substances with positive enthalpies of solution
always to be soluble. B) We can expect substances with positive enthalpies of
solution always to be soluble only if the entropy of solution is negative. C)
All the other statements are false because the solute always affects the
solvent resulting in a negative entropy of solution. D) We can expect
substances with negative enthalpies of solution always to be soluble.
10.B
Which of the following is NOT the effect of adding non-volatile solute to the
liquid? (A). Decreased vapor pressure (B). Increased melting point (C).
Increased osmotic pressure (D). Increased boiling point
11.C
Calculate the number of moles of oxygen that will dissolve in 45 L of water
at 20°C if the partial pressure of oxygen is 0.21 atm. Henry's constant for
oxygen is.0.0013 mol·L-1·atm-1 A) 0.0062 M B) 0.0013 M C) 0.012 M D)
0.00027 M
12.B
The vapor pressure of methanol at 25°C is 123 Torr and its enthalpy of
vaporization is 35.3 kJ·mol-1. Estimate the normal boiling point of
methanol. Assume the enthalpy of vaporization is independent of temperature.
A) 450 K B) 342 K C) 315 K D) 373 K
13.B
Consider the reaction Calculate the equilibrium constant for this reaction at
525°C. A) 3.04 x 10-3 B) 8.07 x 10-2 C) 5.20 x 10-7 D) 1.9 x 106
14.D
For the decomposition of ammonia to nitrogen and hydrogen, the equilibrium
constant is 1.47 x 10-6 at 298 K. Calculate the temperature at which K =
0.0100. For this reaction,HΔ轫= 92.38 kJ·mol-1 A) 241K B) 332K C) 59K D)
390K
15.D
Which of the following statements is true? A) When the value of Q is large,
the equilibrium lies on the product side of the equilibrium reaction. B) When
the value of K is large, the equilibrium lies on the reactant side of the
equilibrium reaction. C) A small value of K means that the equilibrium
concentrations of the reactants are small compared to the equilibrium
concentrations of the products. D) A large value of K means that the
equilibrium concentrations of products are large compared to the equilibrium
concentrations of the reactants.
16.D
For the reaction NH3+H2S←→NH4HS(s) Kc = 9.7 at 900 K. If the initial
concentrations of NH3(g) and H2S(g) are 2.0 M, what is the equilibrium
concentration of H2S(g)? A) 1.9 M B) 0.20 M C) 1.7 M D) 0.32 M
17.C
Consider the following reaction at a certain temperature: K=0.420 If 2.0 mol
of H2(g) and I2(g), and 0.10 mol HI(g) were mixed in a 1.0 L flask, then A)
the concentration of I2 (g) would increase. B) the value of K would increase
to 400. C) the concentration of HI(g) would increase. D) no change would
occur.
18.A
Consider the reaction At 298 K, Kc = 1.3x10-3, whereas at 783 K, Kc =
2.2x10-2. Which of the following is true? A) The reaction is endothermic. B)
At 783 K, more HI(g) is produced. C) At 298 K, K = 3.2 X 10-2. D) At 298 K,
the reaction is likely to be spontaneous.
19.C
A certain enzyme-catalyzed reaction in a biochemical cycle has an equilibrium
constant that is 1000 times the equilibrium constant of the next step in the
cycle. If the standard Gibbs free energy of the first reaction is –200 kJ·
mol-1, what is the standard Gibbs free energy of the second reaction? A) –
140 kJ·mol-1 B) –160 kJ·mol-1 C) –180 kJ·mol-1 D) –200 kJ·mol-1
20.A
Which of the following is the weakest acid? A) HClO B) HClO2 C) HClO3 D) HClO4
21.D
Which of the following produces the strongest conjugate base? A) HF (pKa =
3.45) B) HCIO (pKa = 7.53) C) HCOOH (pKa = 3.75) D) HIO (pKa = 10.64)
22.B
Which of the following species is the Lewis base? A)BF3 B)NH3 C)SO2 D)H+
23.B
HBrO(aq), in a 0.25 M solution, has a pKa = 8.69. What is its pH? A) 0.60 B)
4.65 C) 5.90 D) 8.10
24.B
The amino acid methionine, HOOC-CH(CH2CH2SCH3)NH3+, has pKa1 = 2.2 and pKa2 =
9.1. If this amino acid is represented by H2L+, the major species at pH 6 is
A) H2L+ B) HL C) L-
25.A
Which reaction has a positive ΔHo?
17.C
Consider the following reaction at a certain temperature: K=0.420 If 2.0 mol
of H2(g) and I2(g), and 0.10 mol HI(g) were mixed in a 1.0 L flask, then A)
the concentration of I2 (g) would increase. B) the value of K would increase
to 400. C) the concentration of HI(g) would increase. D) no change would
occur.
18.A
Consider the reaction At 298 K, Kc = 1.3x10-3, whereas at 783 K, Kc =
2.2x10-2. Which of the following is true? A) The reaction is endothermic. B)
At 783 K, more HI(g) is produced. C) At 298 K, K = 3.2 X 10-2. D) At 298 K,
the reaction is likely to be spontaneous.
19.C
A certain enzyme-catalyzed reaction in a biochemical cycle has an equilibrium
constant that is 1000 times the equilibrium constant of the next step in the
cycle. If the standard Gibbs free energy of the first reaction is –200 kJ·
mol-1, what is the standard Gibbs free energy of the second reaction? A) –
140 kJ·mol-1 B) –160 kJ·mol-1 C) –180 kJ·mol-1 D) –200 kJ·mol-1
20.A
Which of the following is the weakest acid? A) HClO B) HClO2 C) HClO3 D) HClO4
21.D
Which of the following produces the strongest conjugate base? A) HF (pKa =
3.45) B) HCIO (pKa = 7.53) C) HCOOH (pKa = 3.75) D) HIO (pKa = 10.64)
22.B
Which of the following species is the Lewis base? A)BF3 B)NH3 C)SO2 D)H+
23.B
HBrO(aq), in a 0.25 M solution, has a pKa = 8.69. What is its pH? A) 0.60 B)
4.65 C) 5.90 D) 8.10
24.B
The amino acid methionine, HOOC-CH(CH2CH2SCH3)NH3+, has pKa1 = 2.2 and pKa2 =
9.1. If this amino acid is represented by H2L+, the major species at pH 6 is
A) H2L+ B) HL C) L-
25.A
Which reaction has a positive ΔHo?
II. Integrated Questions (40%)
1. (10 points, 2 for each quantity) A quantity of 0.35 mole of an ideal gas
initially at 20oC is expanded from 1.2 L to 7.4 L. Calculate the values of w,
q,UΔ,sysSΔandGΔ when the process is carried out isothermally and
irreversibly
against an external pressure of 1.0 atm.
2. (9 pts) The phase diagram of water is listed on the right.
(a). What kind of physical state of water is at 1 atm, 200℃?
(b). Given dPSdTVΔ=Δ, Explain why the AD line has a negative steep slope
while AB curve has a positive curvature.
(c). Which point is the “critical point” in this phase diagram? What
happens beyond this critical point?
(g
w = -630 J , q= 630 J , UΔ= 0 ,sysSΔ= 5.3 J K-1 ,GΔ= -1.5 kJ
(a) vapor
(b) AD line, liquid->ice, VΔ> 0, SΔ<< 0, so dPSdTVΔ=Δ<<0, AD line has a
negative steep.
(c) AB line, liquid-> vapor, VΔ< 0, SΔ> 0, so dPSdTVΔ=Δ>0, AB line has a
positive steep.
(d) C. The heat of vaporization is zero at and beyond this critical point, so
there is no distinction between the two phases. The equilibrium system is a
homogeneous supercritical fluid.
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