Calculate the heat change in calories for freezing 65 g of water at 0 ∘C.

Question

Express your answer as a positive value using two significant figures and include the appropriate units.

Answer 1

Assuming the water is already at 0ºC and you just now want to freeze it, you use the ∆Hfusion which is 334 J/g

65 g x 334 J/g = 21,710 J x 1 cal/4.184 J = 5189 cal = 5200 calories (to 2 significant figures)