I didn't say anything about not turning to gas by changing space. I said the vapor pressure of a liquid--the pressure of the gas form of _that_ substance over the liquid form of that stubstance--is constant based on temperature and pressure of that gas and only that gas. But it takes more of a gas to achieve the same pressure in a greater volume. One atmosphere of gas in a 12 oz bottle is a hell of a lot less gas than one atmosphere in a room.

And as stated, it's all partial pressures. More Nitrogen pressure doesn't affect the pressure of gasoline vapor. LNG is liquid because it's under pressure. But it's not pressurized by adding a lot of air, it's pressurized by compressing it until it achieves liquid state.