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Advanced Chemistry Thermochemistry test
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Thermochemistry Practice Test
NOTE: THIS TEST HAS NOT YET BEEN CHECKED FOR ERRORS
1. 100 mL of water is placed in a coffee cup calorimeter. When 1.0 g of an ionic solid is added, the
temperature decreases from 21.5oC to 20.8oC as the solid dissolves. The dissolving of the solid is a process
a) that is exothermic, b) that has delta Suniv > 0, c) that has delta Ssys < 0, d) that has delta Ssurr > 0
2. Name the first law of thermodynamics.
3. Name the second law of thermodynamics.
4. Name the third law of thermodynamics
5. For a particular chemical reaction
delta H = 5.5 kJ and delta S = -25 J/K
Under what temperature conditions is the reaction spontaneous?
a) When T < -220 K., b) When T < 220 K., c) The reaction is spontaneous at all temperatures.
d) The reaction is not spontaneous at any temperature., e) When T > 220 K.
6. The following processes are to be considered at 298 K:
I. H2O(l) ---> H2O(g)
II. Cl2(g) ---> 2Cl(g)
III. 2Fe(s) + (3/2)O2(g) ---> Fe2O3(s)
IV. NaCl(s) --->NaCl(aq)
V. CaC2(s) + 2H2O(l) ---> C2H2(g) + Ca(OH)2(s)
VI. N2(g, 1 atm) ---> N2(g, 2 atm)
For which is delta S positive?
a) I, II, IV, V,
b) I, IV, V
c) I, IV, V, VI
d) III, VI
e) all six processes
7. Consider the hypothetical reaction which proceeds at 310 K. Standard free energies in kJ/mol are given in
parentheses.
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Advanced Chemistry Thermochemistry test
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http://www.vernonteach.net/units/ptests/thermotest.html
B ----> C delta Go = -31.4 kJ/mol
(B=?) (C=176.4)
What is the standard free energy of compound B in kJ/mol?
a) 207.8,b) -207.8,c) 145.0,d) -145.0,
8. For the reaction Cl2O(g) + (3/2)O2(g) ---> 2ClO2(g),
delta Ho = 126.4 kJ/mol and delta So = -74.9 J/K mol. At 377oC, delta Go equals:
a) 98.3 kJ/mol, b) 77.8 kJ/mol, c) 175.1 kJ/mol, d) 51.5 kJ/mol
9. Calculate the work for the expansion of CO2 from 1.0 to 2.5 liters against a pressure of 1.0 atm at constant
temperature.
a) 1.5 liter-atm,b) 2.5 liter-atm,c) 0,d) -1.5 liter-atm,e) -2.5 liter-atm
10. What is the heat capacity of mercury if it requires 167 J to change the temperature of 15.0 g mercury
from 25.0oC to 33.0oC?
a) 6.92 x 10-3 J/g oC, b) 1.12 x 10-2 J/g oC, c) 0.445 J/g oC, d) 1.39 J/g oC, e) 313 J/g oC
11. Calculate delta Ho for the reaction C4H4(g) + 2H2(g) ---> C4H8(g), using the following data:
delta Hocombustion for C4H4(g) = -2341 kJ/mol
delta Hocombustion for H2(g) = -286 kJ/mol
delta Hocombustion for C4H8(g) = -2755 kJ/mol
a) -128 kJ, b) -158 kJ, c) 128 kJ, d) 158 kJ
12.Given the heats of the following reactions:(delta H (in KJ) values are given on the far right of each
reaction)
I. P 4(s) + 6Cl2(g) >4PCl3(g) -1225.6
II. P4(s) + 5O2(g) > P 4O10(g) -2967.3
III. PCl3(g) + Cl2(g)> PCl5(g) -84.2
IV. PCl3(g) + 1/2 O2(g) > Cl3PO(g) -285.7
Calculate the value of delta H for the reaction below:
P4O10(s) + 6PCl5(g) > 10Cl3PO(g)
a) -110.5 kJ, b) -610.1 kJ, ) -2682.2 kJ, d) -7555.0 kJ
ANSWERS
12/14/2010 11:29 AM
Advanced Chemistry Thermochemistry test
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http://www.vernonteach.net/units/ptests/thermotest.html
1. b 2-4 see notes 5. d 6. a 7. a 8. c 9. d 10. d 11.d 12. b
12/14/2010 11:29 AM