AP ChemistryName :
Worksheet – 37-60-3Date :
CALCULATORS MAY NOT BE USED ON THE MULTIPLE CHOICE:
_____ 1. Reacts with water to form a base (hydroxide).
_____ 2. Reacts with water to form an acid.
_____ 3. Toxic, combustible, nonmetallic oxide.
_____ 4. Inert gas.
_____ 5. Yellow-green gas which is very toxic.
_____ 6. Weak acid
_____ 7. Weak base
_____ 8. Forms a gas when reacted with a strong acid
_____ 9. Forms a neutral solution
_____ 10. Strong acid
_____ 11. Ammonia can be produced by the Haber process which has the reaction 3H2(g) + N2(g) 2 NH3(g). How many liters (at STP) of ammonia can be produced from 9.1 g of hydrogen gas and 56.4 g of nitrogen gas?
a. 90. Lb. 120 Lc. 1.0 x 102 L d. 67 Le. 45 L
_____ 12. The reaction of Cl2 gas and methane gas occurs by the equation 4 NH3(g) + 5O2(g) 4NO(g) + 6 H2O(g). If 50. mL of ammonia gas are combined with an 75 mL of oxygen gas at a constant temperature and pressure, what will the final volumes of NH3(g), O2(g), NO(g) and H2O(g) be?
a. 0 mL, 25 mL, 50. ml, 60. mL
b. 13 mL, 0 mL, 60 ml, 75 mL
c. 15 mL, 25 mL, 15 ml, 60. mL
d. 5 mL, 0 mL, 63 ml, 75 mL
e. 0 mL, 13 mL, 50. ml, 75 mL
_____ 13. For the dissociation reaction of the acid HF : HF(aq) H+(aq) + F-(aq) ΔS is observed to be negative. Which of the following are true?
a. This is unexpected since each HF molecule produces two ions when it dissociates.
b. The value of ∆S indicates an increase in order.
c. Water molecules must become more orderly as they surround the ions in solution.
d. Hydration of the ions produces the negative value of ΔS.
e. All of the above.
_____ 14. (T/F) All real processes are irreversible.
_____ 15. (T/F) According to the second law of thermodynamics, entropy is always increasing.
_____ 16. When a stable diatomic molecule is dissociated into its atoms under normal conditions, what are the signs of ΔHº, ΔSº, and ΔGº? (e.g. Cl2 2 Cl) (Hint: not normally a spontaneous reaction).
ΔHº ΔSº ΔGº
a. + + +
b. + - -
c. - + +
d. - - +
e. - - -
_____ 17. The above reaction is expected to be
a. always spontaneous.
b. spontaneous at low temperatures, but not high temperatures.
c. spontaneous at high temperatures, but not low temperatures.
d. never spontaneous.
_____ 18. When water spontaneously condenses into a liquid at constant pressure, what are the signs of ΔHº, ΔSº, and ΔGº?
ΔHº ΔSº ΔGº
a. + + +
b. + - -
c. - + +
d. - - +
e. - - -
_____ 18. For the reaction 2SO3(g) 2SO2(g) + O2(g) + heat , what are the signs of ΔHº, ΔSº, and ΔGº?
ΔHº ΔSº ΔGº
a. + + +
b. + - -
c. - + -
d. - - +
e. - - -
_____ 19. According to the above, the above reaction is expected to be
a. always spontaneous.
b. spontaneous at low temperatures, but not high temperatures.
c. spontaneous at high temperatures, but not low temperatures.
d. never spontaneous.
_____ 20. For a certain reaction A ↔ B at 300. K, the 15 kJ of heat are released. What is the change in entropy of the surroundings in J/K?
a. 0.0 J/K
b. -25 J/K
c. -50. J/K
d. 25 J/K
e. 50. J/K
21. Given the following data(Hint : Hess’s Law)
C2H2(g) + 5/2 O2(g) 2CO2(g) + H2O(l)∆Gº = -1234 kJ
C(s) + O2(g) CO2(g)∆Gº = -394 kJ
H2(g) + ½ O2(g) H2O(l)∆Gº = -237 kJ
Calculate ∆Gº for the reaction 2C(s) + H2(g) C2H2(g)
22. Calculate ∆G for the reaction NO(g) + O3(g) ——> NO2(g) + O2(g) for these conditions:
T = 298 K
PNO = 1.00 x 10-6 atm, PO3 = 2.00 x 10-6 atm
PNO2 = 1.00 x 10-7 atm, PO2 = 1.00 x 10-3 atm
23. Consider the reaction 2SO3(g) ↔ 2SO2(g) + O2(g)
For each of the following mixtures of reactants and productsat 25°C, predict the direction in which the reaction will shiftto reach equilibrium.
a. PSO2 = PO2, = PSO3 = 1.00 atm
b. PSO2 = PO2 = 1.00 x 10-9 atm, PSO3 = 1.00 atm
24. One of the reactions that destroys ozone in the upper atmosphere is NO(g) + O3(g) ↔ NO2(g) + O2(g)
Using data from Appendix 4, calculate ∆G° and K (at 298 K) for this reaction.
25. Consider the reaction H2(g) + Cl2(g) ↔ 2 HCl(g)
- Calculate ∆H°, ∆S°, ∆G°, and K (at 298 K) using data in Appendix 4
26a. The autoionization of water at 25°C, H2O(/) ↔ H+(aq) + OH-(aq) has the equilibrium constant 1.00 x 10-14. Calculate ∆G° for this process at 25°C.
b. At 40°C, Kw = 2.92 x 10-14. Calculate ∆G° at 40.°C.
27. A green plant synthesizes glucose by photosynthesis, as shown in the reaction
6CO2(s) + 6H2O(/) C6H12O6(s) + 6O2(g)
Animals use glucose as a source of energy:
C6H12O6(s) + 6O2(g) —— > 6CO2(g) + 6H2O(/)
If we were to assume that both these processes occur to the same extent in a cyclic process, what thermodynamic property must have a nonzero value?
28. Elemental sulfur can exist in two crystalline forms, rhombic and monoclinic. Calculate the temperature for the conversion of monoclinic sulfur to rhombic sulfur given the following data:
∆Hºf (kJ/mol) / ∆Sºf (J/K∙mol)S (rhombic) / 0 / 31.73
S (monoclinic) / 0.30 / 32.55
Answers : 21. ∆Gº = 209 kJ 22. ∆G = -188 kJ 23a. ∆G = 142 kJ, since ∆G is positive, this reaction is spontaneous in the reverse direction, and the reaction will shift to the left to reach equilibrium. 23b. ∆G = -1.2 x 104 J, since ∆G is negative, this reaction is spontaneous in the forward direction, and the reaction will shift to the right to reach equilibrium. 24. 5.07 x 1034 25a. ∆Hº = -184 kJ, ∆Sº = 20. J/K, ∆Gº = -190. kJ, K = 2.01 x 1033 26a. 79.9 kJ/mol 26b. 81.1 kJ/mol 27. According to the second law of thermodynamics, no real process is irreversible and ∆Suniv must increase. 28. 370 K