Which is a drawback to the use of oil shale to produce energy

Explanation:

Shale oil extraction is a very expensive process. Mining and processing techniques are very costly. Mining of shells of rock have environmental damaging effect. Mining techniques also releases carbon dioxide, so increases global warming. Mining of shale oil also requires large amount of water and it can also contaminate ground water. Waste disposal is also expensive.

answer: 802.3 kilo joules of energy represents 191.75 kilo calorie of energy.

explanation:

energy released during combustion of one mole methane = 802.3 kilo joules

if 1 kilo joule = 0.239006   kilo calorie

then ,802.3 kilo joule will be = 802.30.239006 kilo calorie

802.3 kilo joule = 191.75 kilo calorie

hence, the energy in kilo calorie is 191.75 kilo calorie.