Question 1: Evaluating Fuels using Heats of Combustion (35 points)
The heats of combustion of ethane (C2H6) and butane (C4H10) 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 CO2?
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 CO2 produced by burning 1000 kJ of each fuel: (9 points total)
Question 2: Estimating CO2 emissions based on energies (30 points)
Estimate the impact on CO2 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 CO2 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)