Question 1: Evaluating Fuels using Heats of Combustion (35 points)

The heats of combustion of ethane (C 2 H 6 ) and butane (C 4 H 10 ) are 52 kJ/g and 49 kJ/g, respectively. I want to produce 1000 kJ by burning one of the fuels. Which fuel will emit the least amount of CO 2 ?

1. Calculate the number of grams needed of each fuel: (6 points total)

2. Calculate the number of moles of each fuel: (12 points total)

3. Write down the balanced chemical equation for the combustion of the fuels: (8 points total)  

4. Calculate the number of moles of CO 2 produced by burning 1000 kJ of each fuel: (9 points total)  

 Question 2: Estimating CO 2 emissions based on energies (30 points)

Estimate the impact on CO 2 emissions if Americans switched all incandescent light bulbs to fluorescent light bulbs. Is this plan feasible/worthwhile? We use a 13 W fluorescent light bulbs to replace a 60 W incandescent light bulb. 1 W=1J/s
a) Assume one light bulb/household is replaced. There are 124.6 million households in the United States.

(12 points total)

The average light-on time per household is 4 hours per day. How much electric

energy will be saved by replacing 60 W incandescent light bulbs with 13 W fluorescent light bulbs in USA per day.

b) Assume these electricity is obtained by combustion of methane, how many tons of CO 2 will be released to produce the electricity? The energy efficiency of power plant is 33%. The combustion heat of methane is 802 kJ/mole. (18 points total)