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CHEM 3401 Physical Chemistry 1 Spring 2014 Problem Set 4: Thermochemistry & Heat Engines Assigned: Wednesday, February 5, 2014 Due: in lecture on Thursday, February 13, 2014 A. Recommended Reading Chapter 4 Sections 5.1-5.3, 5.11, & 5.14 B. Recommended Practice Problems Qualitative Question 1 Q4.8 Qualitative Question 2 Q4.13 Qualitative Question 3 Q5.17 Quantitative Problem 1 a. P4.17(c, d, & e only) Use data in Tables 4.1 & 4.2 in Appendix B b. P4.8(b & c only) Quantitative Problem 2 a. The dipeptide glycylglycine C4H8N2O3(s) has a standard enthalpy of complete combustion at 298.15 K, € ?Hcomb ? , of -1969 kJ/mol, where ?Hcomb = ?Hrxn for a complete combustion reaction for one mole of the substance. In this reaction the only products are carbon dioxide gas, nitrogen gas, and liquid water. Determine q, w, ?U, and ?H (in kJ) when 10.0 g of this dipeptide are burned at 298.15 K and a constant pressure of 1 bar. Assume ideal gas behavior for all gases. b. Consider the following reaction: C4H8N2O3(s) + 3 O2(g) ? CH4N2O(s) + 3 CO2(g) + 2 H2O(l) for which € ?Hrxn ? (298.15 K) = -1340.1 kJ/mol. Determine € ?Hrxn ? (330.15 K) (in kJ/mol) using data in Tables 4.1 & 4.2, CP,m(C4H8N2O3(s), 1 bar) = 163.6 J/mol-K, and assuming all heat capacities are constant between 298.15 K and 330.15 K.
CHEM 3401 Physical Chemistry 1 Spring 2014 2 Quantitative Problem 3 a. A nuclear power plant is designed to produce 500 MW of electrical power. The hightemperature heat absorption in the boiler occurs at 360. °C. Condensation for removal of heat from the cycle will be done at 25. °C using cooling water. What is the minimum mass flow rate of cooling water (in kg/s) needed if federal regulations issued by the Environmental Protective Agency limit the temperature rise for the cooling water to 2.00 °C? Assume maximum thermodynamic efficiency and a constant specific heat capacity at constant pressure for H2O(l) of 4.184 J/g-K. b. P5.3 Use € ?Hfus,H2O = 6.008 kJ/mol C. Required Problems Submit…