Chemistry 105 Exam II October 26, 2007
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Multiple choice (3 pts. each) DARKEN THE CORRECT ANSWER ON THE ANSWER
SHEET. Remember there are also 4 problems given after the multiple-choice questions.
Budget your time accordingly.
1. Which process is not exothermic?
a) Burning wood
b) Making ice
c) Boiling water
d) Condensation of water vapor
e) all of the above
2. Determine E for a system that absorbs 67.8 kJ of heat while doing 46.9 kJ of work on the
surroundings.
a) -114.7 kJ
b) 20.9 kJ
c) 67.8 kJ
d) 114.7 kJ
e) -20.9 kJ
3. The specific heat of toluene, C7H8, is 1.13 J/g-K. How many joules of heat are needed to raise
the temperature of 35.0g from 11.8C to 29.0C?
a) 2.30 J b) 39.6 J
c) 680 J d) 19.4 J
4. Which of the following statements is/are true concerning E?
a) When PV is small, E approximates H.
b) E is measured at constant volume.
c) The bomb calorimeter is used to measure E.
d) All of the above.
5. Consider the following reactions and their associated values of H°.
B2H6(g) + 3O2(g) B2O3(s) + 3H2O(l)H° = -2147.5 kJ
4B(s) + 3O2(g) 2B2O3(s)H° = -2509.1 kJ
H2(g) + 1/2O2(g) H2O(l)H = -285.85 kJ
What is the standard enthalpy of formation of gaseous diborane, B2H6?
a) 35.4 kJ b) -933.2 kJ c) -3080.7 kJ d) -4259.1kJ
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