Question 1: Evaluating Fuels using Heats of Combustion

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:

2. Calculate the number of moles of each fuel:

3. Write down the balanced chemical equation for the combustion of the fuels:

4. Calculate the number of moles of CO₂ produced by burning 1000 kJ of each fuel:

Question 2: Estimating CO₂ emissions based on energies.

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.

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.