Spring 2006 CH302 Worksheet 1b:
Examples of Simple Thermodynamics Multiple Choice Problems
1. Which of the following is a correct statement concerning the Second Law of Thermodynamics?
1. The free energy of a system is temperature dependent.
2. Entropy of a system increases in the phase change from a liquid to a gas.
3. Energy cannot be created nor destroyed.
4. The entropy in the universe is conserved.
2. 75 g of a potato chips are burned in a calorimeter that contains 2 liters of water
initially at 297K. After the combustion, the temperature rises 12oC. How much heat is evolved per gram of
potato chip burned? The heat capacity of the calorimeter is 200 J/oC? The density of water is 1.0 g/ml. The
specific heat of water is 4.18 J/goC.
1. 7.1 kJ/g
2. 100.3 kJ/g
3. 102.7 kJ/g
4. 1.37 kJ/g
3. What is the change of enthalpy associated with the combustion of one mole of ethylene?
C2H4 + 3O2 Æ 2CO2 + 2H2O
1. 0 kJ
2. -1323 kJ
3. +1323 kJ
4. -3230 kJ
5. +3230 kJ
4. For the combustion reaction of acetaldehyde (C2H4O)
2C2H4O + 5O2 Æ 4CO2 + 4H2O
assume all reactants and products are gases and calculate the ΔH0rxn using the following
bond energy values:
C-C BE = 611 kJ/mol
C-H BE = 413 kJ/mol
O=O BE = 498 kJ/mol
C=O BE = 799 kJ/mol
H-O BE = 463 kJ/mol
1. -1080 kJ/mol
2. +1080 kJ/mol
3. 0 kJ/mol
4. -2303 kJ/mol
5. +2303 kJ/mol
