AP Environmental Science 6.5: Fossil Fuels

$7.4 \times 10^{7}$ cubic meters of natural gas were extracted from a large deposit in 2020. An average of 4.76 kWh of electricity can be generated from each cubic meter of natural gas combusted. In 2020, an average home consumed 10,715 kWh of electricity. Calculate how many homes could have been provided with electricity by natural gas extracted from the large deposit in 2020. Show your work.

One point for the correct setup to calculate how many homes could have been provided with electricity by natural gas:

Accept one of the following:

- $\left(7.4 \times 10^{7} \mathrm{~m}^{3}\right) \times \frac{4.76 \mathrm{kWh}}{1 \mathrm{~m}^{3}} \times \frac{1 \text { home }}{10,715 \mathrm{kWh}}$

- $\left(7.4 \times 10^{7} \mathrm{~m}^{3}\right) \times \frac{4.76 \mathrm{kWh}}{10,715 \mathrm{kWh}}$

- $\left(7.4 \times 10^{7}\right) \times \frac{4.76}{10,715}$

1 point

One point for the correct calculation of how many homes could have been provided with electricity by natural gas:

Accept one of the following:

- 32,874

- 32,873

- 33,000

1 point

Total for part (f)

2 points

In 2021, $8.99 \times 10^{11} \mathrm{kWh}$ of electricity was generated through the combustion of coal. One kilogram of carbon dioxide is produced per kWh of electricity generated by combusting coal, while 0.42 kilograms of carbon dioxide is produced by combusting natural gas. Calculate how much less carbon dioxide would have been produced in 2021 if all coal-burning power plants were replaced with natural gas-burning power plants. Show your work.

One point for the correct setup to calculate how much less carbon dioxide would have been produced in 2021:

Accept one of the following:

- $\frac{(1.0 \mathrm{~kg}-0.42 \mathrm{~kg})}{1 \mathrm{kWh}} \times\left(8.99 \times 10^{11} \mathrm{kWh}\right)$

- $(1.0 \mathrm{~kg}-0.42 \mathrm{~kg}) \times\left(8.99 \times 10^{11} \mathrm{kWh}\right)$

- $(1.0-0.42) \times\left(8.99 \times 10^{11}\right)$
- $\left(\frac{8.99 \times 10^{11} \mathrm{kWh}}{1} \times \frac{1 \mathrm{~kg}}{\mathrm{kWh}}\right)-\left(\frac{8.99 \times 10^{11} \mathrm{kWh}}{1} \times \frac{0.42 \mathrm{~kg} \mathrm{CO}}{\mathrm{kWh}}\right)$, THEN $8.99 \times 10^{11} \mathrm{~kg} \mathrm{CO}_{2}-3.776 \times 10^{11} \mathrm{~kg} \mathrm{CO}_{2}$

One point for the correct calculation of how much less carbon dioxide would have been 1 point produced in 2021:

Accept one of the following:

- 521 billion kg

- 521,420,000,000 kg

- $5.2142 \times 10^{11} \mathrm{~kg}$

- $5.21 \times 10^{11} \mathrm{~kg}$

- $5.2 \times 10^{11} \mathrm{~kg}$

Total for part (g)

for question 3

10 points