1. The problem statement, all variables and given/known data Which of the following solid substances can be liquefied simply by increasing the pressure suffciently? ice (H2O) diamond (C) dry ice (CO2) sulfur (S) graphite (C) Which of the following substances cannot be liquified at 1 atm pressure? nitrogen (N2) helium (He) hydrogen (H2) water (H2O) carbon dioxide (CO2) 2. Relevant equations 3. The attempt at a solution I know that some of them are solids, liquids and gases in standard state but I dont know which can be liquified etc. help?