Fuel oil usually is sold by the gallon, gas for cooking by the cubic foot, and coal by the ton. What are the advantages of selling the first two by volume and the last by mass? PLEASE HELP!! (:

Question

anonymous · Answer

you will most of the time handle liquids and gases by volume, because volume is easier measurable and impurenesses will affect mass, but not volume. imagine measuring the weight of a barrel of helium, which is lighter than air. instead, you will be sold that barrel of gas with a certain pressure.

solid substances are handled by mass simply because it's difficult to measure volumes of, say, powders.