Answer to Question #181711 in General Chemistry for Sally

Question

What energy in kcal is needed to change 15.0g of ice at -10°c to 15.0g of water at 0°c?

Answer 1

The specific heat capacity of ice is 2.05 J/g^oC

The heat of fusion of water is 333.55 J/g

Therefore, the total heat equals:

$Q_{total}=c_{ice}m\Delta{T}+c_fm=2.05J/g\cdot\degree{C}\times15.0g\times(0\degree{C}-(-10\degree{C}))+333.55J/g\times15.0g=5310.75J$

$5310.75J\times\frac{1kJ}{1000J}\times\frac{1kcal}{4.1868kJ}=1.27kcal$

Answer: 1.27 kcal