This means that as the pressure increases, the melting temperature increases. Since the diamond-graphite coexistence curve intersects the P axis at , 1atm should be right at the bottom of this diagram. Therefore, if graphite is heated above at 1atm, it should sublime. The boiling temperature of water decreases as we decrease the pressure so we should be able to boil water by sufficiently reducing the pressure of gas over it. The temperature generally drops overnight.
Vapour pressure decreases when the temperature is reduced.
If the temperature drops enough, the partial pressure of water in the air becomes greater than the vapour pressure. The water vapour is no longer in equilibrium and it condenses. The total vapour pressure of the solution is the sum of the vapour pressures of hexane and cyclohexane. We want a percentage by mass so what we really want is . We want a freezing point depression of .