1. Millions of tons of coal are burned every year to produce electricity for humanity. The coal that is burned is a form of pure carbon. (Diamonds and graphite are other forms of pure carbon). A sample of coal is completely burned in a 10.0 L cylinder at a constant pressure of 1.10 atm and a temperature of 1000 oC.

The combustion reaction produces 2.3x104 J of heat energy. As the gaseous products expand they push against a piston which increases the cylinder volume to 55.0 L. After combustion the gases are allowed to reach equilibrium. A chemical analysis shows that there are 15.7 moles of O2 and 9.8 moles of CO2 in the cylinder at equilibrium. A second combustion experiment is carried out at a temperature of 1455 oC. Using the information above calculate the equilibrium constant you would expect to measure for the experiment carried out at the higher temperature.

2. Gasoline currently powers the majority of automobiles in the U.S. but electric cars have been touted as a way to reduce our dependence on gasoline as well as improve our air quality by reducing production of byproducts associated with gasoline combustion. Right now gas costs approximately $4.00 per gallon and electricity costs approximately $0.0818 per kilowatt-hour (kWh). (1 watt (W) = 1 J/s and 1 watt-hour (Wh) = 3600 J). Assume that gasoline is comprised of pure octane (C8H18) and is combusted with pure O2 at constant pressure. How much would you spend on electricity to obtain the same amount of energy as you would get by burning one gallon of gas?