specific heat of water is 4.186 kJ/kgC = 4.186 J/gC

specific heat of ice is 2.06 kJ/kgC

heat of fusion of ice is 334 kJ/kg

energy given up to cool water from 23.2 to 0

E = 7.13g x 4.186 J/gC x 23.2K = 692.4 J

energy given up freezing the water

E = 7.13g x 334 J/g = 2381.4 J

energy given up to cool ice to –12ºC

E = 7.13g x 2.06 J/gC x 12K = 176.3 J

add the three to get 3250 J