phase changes and phase diagrams

[helen123]

hi! thanks for the help the other time. i really need help on this problem

An ice cube tray contains enough water at 22.0°C to make 18 ice cubes that each have a mass of 30.0g. The tray is placed in a freezer that uses CF2Cl2 as a refrigerant. The heat of vaporization of CF2Cl2 is 158 J/g. what mass if CF2Cl2 must be vaporized in the refrigeration cycle to convert all water at 22.0°C at ice at -5.0°C? the heat capacities for H20(s) and H20(l) are 2.03 J/g•°C and 4.18 J/g•°C, respectively, and the enthalpy of fusion for ice is 6.02 kj/mol.

[shengoc]

Consider changes from
H2O(l) at 295 K ---> H2O(l) at 273K ---> H2O(s) at 273 K; this is phase change ---> H2O(s) at 268K

add all the enthalpy contribution from these changes, you are done