Question

How much more energy per gram does petroleum combustion yield relative to coal?

A)2 times
B)4 times
C)6 times
D)8 times

Answer 1

Petroleum combustion yields slightly more energy per gram than coal combustion; it is not 2, 4, 6, or 8 times more, but the energy difference is relatively marginal.

Step-by-step explanation:

The question relates to the energy density of different fuels, specifically how much more energy per gram does petroleum combustion yield relative to coal. The combustion of hard coal has an energy release of about -35 kJ/g, and if we consider petroleum in the form of gasoline, the energy release is approximately 44 kJ/g (considering gasoline's typical energy density of about 31-33 MJ/L and a density of 0.75 kg/L). Therefore, when we compare petroleum to coal, the energy yield of petroleum is not 2, 4, 6, or 8 times more, but rather it is slightly more than that of coal on a per gram basis.