Vapor pressure

The vapor pressure of water at 22 degrees C is 19.800 torr. If you put 26.662 g of water in a cubic container that is 1.1000 m on an edge, will there be any liquid water remaining in the container at 22 degrees C or will it all be vapor? R = 0.0820578 L*atm/K*mol.

Standard heat of fusion

If you want to convert 56.0 g of ice (at 0 degrees C) to water at 75 degrees C, how much propane (CH3-CH2-CH3) would have to burn in order to supply the heat (at constant pressure) to melt the ice and then warm it to the final temperature. Change in standard Heat of fusion = 6.009 kJ/mol and the molar heat capacity of water is 75.376 J/K*mol.

Different melting points

The ions of NaF and MgO are isoelectronic, and the intermolecular distances are about the same (235 pm and 212 pm, respectively). Why then are the melting points of NaF and MgO so different (992 degrees C and 2643 degrees C, respectively)?

Pi and Sigma bonds

Why or why isn't it possible to have pi bonds between two atoms without there being a sigma bond?

Liquifying a compound?

The simple hydrocarbon methane (CH4) cannot be liquefied at room temperature, no matter how high the pressure. Propane (C3H8), another compound in the series of hydrocarbons, has a critical pressure or 42 atm and a critical temperature of 96.8 degrees C. Can this compound be liquefied at room temperature?