Question

What is the minimum mass of 25°c water required to melt all 35.1 g of ice?

Answer 1

ΔH fusion of water is 6.0 kJ/mol
mass of ice = 35.1 g
Molecular weight of water = 18.015 g / mole
number of moles of water = 35.1 / 18.015 = 1.95 mole
amount of heat required to melt ice = moles * Δ H fusion = 1.95 x 6 =11.7 kJ
mass of water at 25°C required to get this energy to a temperature 0°C
q = m C ΔT 
11700 J = m * 4.184 * (25°- 0°)
m = 111.85 g