What happens to the density of a quantity of gas when its temperature is decreased and its pressure is held constant?
Solution 30E As the gas warms it will want to expand and as the pressure is constant it is being allowed to do so. This means that the same number of molecules (the original mass) is now taking up a bigger volume and a density is a measure of mass over volume. Therefore, Density = mass/volume It’s obvious what the density will do because the mass is constant and the volume is increasing. If mass = 10, volume = 20, Density = mass/volume Density = 10/20 Density = 0.5 Then, mass =10, volume = 40, Density = mass/volume = 10/40 Density = 0.25.