1. Calculate ΔE and determine whether the process is endothermic or exothermic for the following cases: (a) q
0.763 kJ and w –840 J; (b) a system releases 66.1 kJ of heat to its surroundings while the surroundings do
44.0 kJ of work on the system; (c) the system absorbs 7.25 kJ of heat from the surroundings while its volume
remains constant (assume that only P-V work can be done). (5 pts)
2. A gas is confined to a cylinder under constant atmospheric pressure. When the gas undergoes a particular
chemical reaction, it absorbs 824 J of heat from its surroundings and has 0.65 kJ of P-V work done on it by
its surroundings. What are the values of ΔH and ΔE for this process? (5 pts)
3. The specific heat of octane, C8H18(l), is 2.22 J g-K. (a) How many J of heat are needed to raise the
temperature of 80.0 g of octane from 10.0 °C to 25.0 °C? (b) Which will require more heat, increasing the
temperature of 1 mol of C8H18(l) by a certain amount or increasing the temperature of 1 mol of H2O(l) by
the same amount? (5 pts)
4. From the enthalpies of reaction: (7 pts)
5. Given the data: (7 pts)
6. Using values from Appendix E, calculate the standard enthalpy change for each of the following reactions:
(10 pts)
7. Using values from Appendix E, calculate the standard enthalpy change for each of the following reactions:
(10 pts)
