Multiple Choice Choose the one alternative that best completes the ...
Multiple Choice Choose the one alternative that best completes the statement or answers the question. 1) For BeCl2, the dipole moment of the molecule, hybridization on the central atom, and number of lone pairs on the central atom are: a) None, sp3, two b) Toward Be, sp2, none c) Away from Be, sp2, one d) Toward Be, sp, one e) None, sp, none
2) Choose the INCORRECT statement about PCI5 a) P has sp3d hybridization. b) Each Cl has 3 lone pairs. c) There are 5
σ
bonds
d) P has one lone pair e) There are no
π
bonds.
3) How would replacing a benzene C and its H with a N atom (C5H5N) affect the delocalized electrons? a) The N can have delocalized electrons like C. b) There would be no delocalized electrons but a double bond between the N and the C on each side of the N c) There would be no delocalized electrons but a double bond between the N and a C d) The molecule would not be stable e) Only the five C atoms would be included in the delocalized electrons.
5) Arrange the following compounds in order of increasing boiling point: I 1-propanol, CH3CH2Ch2OH; II 1,2-propanediol, CH3Ch(OH) CH2OH; III 1,2,3-propanetriol, (glycerol), HOCH2CH(OH)CH2OH a) I, III,II
b) I,II,III
c) III, I,II
d) III,II, I
E) II,III,I
8) The factor that has the largest effect on vapor pressure is: a) Liquid mole weight b) Liquid surface area c) Volume available for vapor d) Molecular dipole moment e) Presence of H bonding 14) Solutions are made that contrain 0.1 moles of each of the following compounds below in 1-g of H2O. Choose the compound whose solution will have the lowest freezing point. a) KCLO3
b) NaBr
c) MgCl2
d) CO2
E) MgSO4
16) Which of the following statements is correct? a) A reaction rate cannot be calculated from the collision frequency alone. b) A zero order reaction depends on the concentrations of reactants. C) The number of collisions has no effect on the rate constant. D) The orientation of a collision does not affect the rate constant. E) a commonly stated rule of thumb is that reaction rates triple for a temperature increase of about 10 oC.
18) For a reaction with a second order rate constant, which is the correct unit? A) M-2 X time b) M X time-2 c) M-1 x time-1 D) M x time-1 E) 1 20) Which of the following lowers the activation energy of a reaction? A) Lowering the temperature B) Adding a catalyst c) Adding a reactants d) Raising the temperature E) Removing products 21) Consider the reaction:
2SO2(g) + O2(g)
↔ 2SO3(g)
Δ Ho = -196.6 kJ/mol
The equilibrium is displaced to the left if: a) The temperature is raised b) Some sulfur dioxide is added c) The pressure is raised d) Some sulfur trioxide is removed e) None of these 25) Write the equilibrium constant expression for the following reaction: 6CO2(g) + 6 H2O(l)
↔ C6H12O6(s) + 6O2(g)
6 C6 H 12 O¿ ¿ a) Kc= ¿ [CO 2 ]6 ¿ H 6 6 [¿ ¿2 O] [CO ] 2 b) Kc= [O2 ]6 ¿ [C 6 H 12 O6 ]
c) Kc=
[H 2 O] [CO 2]
d) KC=
O [¿¿ 2]6 [CO2 ]6 ¿
e) Kc=
[O2 ]6 [CO2 ]
6
6
7) The relationship between the vapor pressure of a liquid and temperature can be expressed by the Clausius-Clapeyron Equation: Log[P2/P1] = [ ∆ Hvap/R] x [1/T1-1/T2]
Ethanol (C2H5OH) has a normal boiling point of 78.3oC and, with
∆ HVap = 39.3 kJ/mol.
What is the vapor pressure of ethanol at 50.0oC? A) 234 torr
B) 354 torr
c) 118 torr
d) 485 torr
E) 670 torr
9) A 0.90 g sample of liquid water was introduced into an evacuated 2.00 L flask, which was then sealed and heated to 37 oC. What percentage, by mass, of the water remained as liquid? [Vapor pressure of water at 37oc = 48.2 torr] a)82%
b) 90%
c)18%
D)10%
E)0%
12) Henry’s Law constants for aqueous solutions at 25oC are 8.20 x 10-7 molal/mmHg for N2 and 1.62 x 10-6 molal/mmHg for O2. Determine the solubility of nitrogen in water under and atmospheric pressure of 760 mmHg, assuming that air is 80% N2 and 20 % O2. A) 1.25 x 10-4m b) 7.79 x 10-4m c) 4.99x10-4 m d) 6.23 x 10-4m e) 6.16 x 10-3m 13) The vapor pressures of pure propyl alcohol and isopropyl alcohol are 21.0 mmHg and 45.2 mmHg, respectively, at 25oC. What is the composition of the vapor in equilibrium with a propyl alcohol-isopropyl alcohol solution in which the mole fraction of propyl alcohol is 0.250? a) Xiso = 0.750, Xprop = 0.250
B) Xiso=0.317, Xprop = 0.683
C) Xiso = 0.512, Xprop = 0.488
d) Xiso = 0.866, Xprop= 0.134
15) What is the osmotic pressure in mmHg of 6.00L of a 0.108 M solution at 30 oC if three moles of ions are produced in aqueous solution for every mole of solute dissolved? A)2.04 x 103 b) none of these c) 3.68 x 104 d) 8.05 e) 6.13 x 103 17) For the reaction: 2N2O5(g)
→ 4NO29g) + O2(g) the rate law is:
O ¿ 2 ¿ ¿ =K[ n2 o5 ¿ ¿ ∆¿ ¿ At 300k, the half-life is 2.50 x104 seconds and the activation energy is 1033 KJ/mol. What is the rate constant at 350 K? a) 6.38 x1016 s-1 b) 4.78 s-1 c) 7.47 x 10-8s-1 d) 1.03 x 10-2S-1 e) E) 2.79 x 10-5s-1 19) What is the rate law for the following reaction and mechanism? 2HgCl2 + C2O42-
→ 2Cl- + 2CO2 + Hg Cl2
HgCl 2 + C2O42-
↔ Hg CL2C2O42-
HgCl2C2O42- + C2O42- → Hg + HgCl2
(Fast)
Hg +2Cl- + CO2 + C2O4CO22- (Slow)
→ HgCl2
C2O4CO22- →
(overall reation)
(fast)
C2O42- +CO2
(Fast)
a) Rate = K [HgCl2]2[C2O42-]2 b) Rate = k[HgCl2]2[C2O42-] c) Rate =k[HgCl2] d) Rate = K[HgCl2][C2O42-]2 e) Rate = k[HgCl2][C2O42-] 22) For the decomposition of SO3 (g), kc= [SO2]2[O2]/[SO3]2, at equilibrium are 0.090 mol SO2, 0l110 mol O2, 0.100 mol SO3 in a 25.0-L container. What is the value of Kc? a) 3.6 x 10-3
B) 2.23
C) 0.040
D) 0.089
23) What is the relationship between Kp and Kc for the reaction below? 4NH3(g) + 7O2(g) ↔ 2N2O4(g) + 6H2O(g)
E) 7.89
A) Kc=Kp (RT)-3
b) kp=Kc(RT)3
C) Kp=Kc(RT)
D) Kp=Kc(RT)-3
2) Choose the INCORRECT statement about PCI5 a) P has sp3d hybridization. b) Each Cl has 3 lone pairs. c) There are 5
σ
bonds
d) P has one lone pair e) There are no
π
bonds.
3) How would replacing a benzene C and its H with a N atom (C5H5N) affect the delocalized electrons? a) The N can have delocalized electrons like C. b) There would be no delocalized electrons but a double bond between the N and the C on each side of the N c) There would be no delocalized electrons but a double bond between the N and a C d) The molecule would not be stable e) Only the five C atoms would be included in the delocalized electrons.
5) Arrange the following compounds in order of increasing boiling point: I 1-propanol, CH3CH2Ch2OH; II 1,2-propanediol, CH3Ch(OH) CH2OH; III 1,2,3-propanetriol, (glycerol), HOCH2CH(OH)CH2OH a) I, III,II
b) I,II,III
c) III, I,II
d) III,II, I
E) II,III,I
8) The factor that has the largest effect on vapor pressure is: a) Liquid mole weight b) Liquid surface area c) Volume available for vapor d) Molecular dipole moment e) Presence of H bonding 14) Solutions are made that contrain 0.1 moles of each of the following compounds below in 1-g of H2O. Choose the compound whose solution will have the lowest freezing point. a) KCLO3
b) NaBr
c) MgCl2
d) CO2
E) MgSO4
16) Which of the following statements is correct? a) A reaction rate cannot be calculated from the collision frequency alone. b) A zero order reaction depends on the concentrations of reactants. C) The number of collisions has no effect on the rate constant. D) The orientation of a collision does not affect the rate constant. E) a commonly stated rule of thumb is that reaction rates triple for a temperature increase of about 10 oC.
18) For a reaction with a second order rate constant, which is the correct unit? A) M-2 X time b) M X time-2 c) M-1 x time-1 D) M x time-1 E) 1 20) Which of the following lowers the activation energy of a reaction? A) Lowering the temperature B) Adding a catalyst c) Adding a reactants d) Raising the temperature E) Removing products 21) Consider the reaction:
2SO2(g) + O2(g)
↔ 2SO3(g)
Δ Ho = -196.6 kJ/mol
The equilibrium is displaced to the left if: a) The temperature is raised b) Some sulfur dioxide is added c) The pressure is raised d) Some sulfur trioxide is removed e) None of these 25) Write the equilibrium constant expression for the following reaction: 6CO2(g) + 6 H2O(l)
↔ C6H12O6(s) + 6O2(g)
6 C6 H 12 O¿ ¿ a) Kc= ¿ [CO 2 ]6 ¿ H 6 6 [¿ ¿2 O] [CO ] 2 b) Kc= [O2 ]6 ¿ [C 6 H 12 O6 ]
c) Kc=
[H 2 O] [CO 2]
d) KC=
O [¿¿ 2]6 [CO2 ]6 ¿
e) Kc=
[O2 ]6 [CO2 ]
6
6
7) The relationship between the vapor pressure of a liquid and temperature can be expressed by the Clausius-Clapeyron Equation: Log[P2/P1] = [ ∆ Hvap/R] x [1/T1-1/T2]
Ethanol (C2H5OH) has a normal boiling point of 78.3oC and, with
∆ HVap = 39.3 kJ/mol.
What is the vapor pressure of ethanol at 50.0oC? A) 234 torr
B) 354 torr
c) 118 torr
d) 485 torr
E) 670 torr
9) A 0.90 g sample of liquid water was introduced into an evacuated 2.00 L flask, which was then sealed and heated to 37 oC. What percentage, by mass, of the water remained as liquid? [Vapor pressure of water at 37oc = 48.2 torr] a)82%
b) 90%
c)18%
D)10%
E)0%
12) Henry’s Law constants for aqueous solutions at 25oC are 8.20 x 10-7 molal/mmHg for N2 and 1.62 x 10-6 molal/mmHg for O2. Determine the solubility of nitrogen in water under and atmospheric pressure of 760 mmHg, assuming that air is 80% N2 and 20 % O2. A) 1.25 x 10-4m b) 7.79 x 10-4m c) 4.99x10-4 m d) 6.23 x 10-4m e) 6.16 x 10-3m 13) The vapor pressures of pure propyl alcohol and isopropyl alcohol are 21.0 mmHg and 45.2 mmHg, respectively, at 25oC. What is the composition of the vapor in equilibrium with a propyl alcohol-isopropyl alcohol solution in which the mole fraction of propyl alcohol is 0.250? a) Xiso = 0.750, Xprop = 0.250
B) Xiso=0.317, Xprop = 0.683
C) Xiso = 0.512, Xprop = 0.488
d) Xiso = 0.866, Xprop= 0.134
15) What is the osmotic pressure in mmHg of 6.00L of a 0.108 M solution at 30 oC if three moles of ions are produced in aqueous solution for every mole of solute dissolved? A)2.04 x 103 b) none of these c) 3.68 x 104 d) 8.05 e) 6.13 x 103 17) For the reaction: 2N2O5(g)
→ 4NO29g) + O2(g) the rate law is:
O ¿ 2 ¿ ¿ =K[ n2 o5 ¿ ¿ ∆¿ ¿ At 300k, the half-life is 2.50 x104 seconds and the activation energy is 1033 KJ/mol. What is the rate constant at 350 K? a) 6.38 x1016 s-1 b) 4.78 s-1 c) 7.47 x 10-8s-1 d) 1.03 x 10-2S-1 e) E) 2.79 x 10-5s-1 19) What is the rate law for the following reaction and mechanism? 2HgCl2 + C2O42-
→ 2Cl- + 2CO2 + Hg Cl2
HgCl 2 + C2O42-
↔ Hg CL2C2O42-
HgCl2C2O42- + C2O42- → Hg + HgCl2
(Fast)
Hg +2Cl- + CO2 + C2O4CO22- (Slow)
→ HgCl2
C2O4CO22- →
(overall reation)
(fast)
C2O42- +CO2
(Fast)
a) Rate = K [HgCl2]2[C2O42-]2 b) Rate = k[HgCl2]2[C2O42-] c) Rate =k[HgCl2] d) Rate = K[HgCl2][C2O42-]2 e) Rate = k[HgCl2][C2O42-] 22) For the decomposition of SO3 (g), kc= [SO2]2[O2]/[SO3]2, at equilibrium are 0.090 mol SO2, 0l110 mol O2, 0.100 mol SO3 in a 25.0-L container. What is the value of Kc? a) 3.6 x 10-3
B) 2.23
C) 0.040
D) 0.089
23) What is the relationship between Kp and Kc for the reaction below? 4NH3(g) + 7O2(g) ↔ 2N2O4(g) + 6H2O(g)
E) 7.89
A) Kc=Kp (RT)-3
b) kp=Kc(RT)3
C) Kp=Kc(RT)
D) Kp=Kc(RT)-3
