Use the table on the right to calculate each required quantity.

the quantity of heat required to melt 175.0 g cu: kj

the mass of a sample of nacl that requires 450.1 kj of heat to melt fully: g

the identity of a substance that releases 21.2 kj of energy when 1.42 mol freezes:

The quantity of heat required to melt 175.0 g Cu can be determined using the heat of fusion of copper, 13.0 kJ/mol.

Heat required = 175 g/ 63.55 g/mol * 13.0 kJ/mol
                         = 35.80 kJ

The mass of a sample of NaCl that requires 450.1 kJ of heat to melt fully:

Use the heat of fusion of NaCl: 30.2 kJ/mol

mass of NaCl = 450.1 kJ/30.2 kJ/mol * 58.44 g/mol
                       = 870.99 g

Rethink and reinvent