define and use specific latent heat and distinguish between specific latent heat of fusion and specific latent heat of vaporisation
explain how molecular movement causes the pressure exerted by a gas and derive and use the relationship pV = ⅓Nm < c² >, where < c² > is the mean-square speed (a simple model considering one-dimensional collisions and then extending to three dimensions using ⅓ < c² > = < cx² > is sufficient)