Question

A 5.00-grain aspirin tablet has a mass of 320 mg. For how many kilometers would the energy equivalent of this mass power an automobile? Assume 12.75 km/L and a heat of combustion of 3.65x10^7 J/L for the gasoline used in the automobile.

Answer 1

Convert the mass (320mg = 0.32kg) to energy in joules J
\[E=mc ^{2}\]
The engine uses 3.65x10^7 J/L so we need to find how many litres of gasoline, G, that energy is equivalent to:
\[\frac{ E }{3.65x10^7 J/L } = G\]
Then we multiply the number of litres of gasoline, G, by the fuel efficiency 12.75 km/L to find the distance in kilometres that it'll take us:
\[G \times 12.75 km/L = distance\]

Answer 2

oops, that mass should be 320mg = 0.32g = 0.00032 kg

Answer 3

Thanks.