Heat of fusion?

Question

1. how much thermal energy is required to completely melt 3.20 mol of ice at 0.0 degrees celcius ?

2. Calculate the amount in moles of ice at 0.0 degres celcius that can be melted by addition of 15.0 kJ of thermal energy.

Answer 1

1. One mole of ice weight 18 grams, so 3.2 moles weigh

57.6 grams.  The heat of fusion of ice is 80 calories per gram

so the total amount of thermal energy is 80 * 57.6 or 4608

calories.  If you want it in joules, 1 calorie = 4.184 joules, so

that is 4608 * 4.184 or 19280 joules (to the nearest joule).

2. The heat of fusion of ice is 80 calories per gram, or

80 * 4.184 =  334.72 joules per gram.  If you add 15 KJ, or

15000 joules of heat energy, you can melt 15000/334.72,

or 44.813 grams of ice at 0°C.

Hope this answers your questions.