1. The problem statement, all variables and given/known data There are two compounds, butane and pentane. one is a liquid at at room temp and the other is gas. which is a liquid and why? 2. Relevant equations 3. The attempt at a solution I'm guessing that its pentane. For a gas to liquify, it should have a have a higher melting point, meaning that it has a higher freeing point. They both only have london dispersion forces but pentane has a greater mass so it should have a higher melting point.