Gases and the absolute scale of temperature — Recall

What equation relates the pressure and volume of a fixed mass of gas at constant temperature, and what does its graph look like?

For a fixed mass of gas at constant temperature, pV = constant, so p1V1 = p2V2. A graph of pressure against volume is a curve showing pressure decreasing as volume increases (inverse relationship); a graph of pressure against 1/volume is a straight line through the origin.