150g of ice is removed from a freezer at a temperature of -15°C. The ice is left, eventually reaching thermal equilibrium with its surroundings at a temperature of 21°C. If the latent heat of fusion for water is 336 kl/kg, the specific heat capacity of ice is 2100 J/kg.°C, and the specific heat capacity of water is 4200J/kg.°C, how much energy goes into the ice? Where does this energy come from?

1 answer

It is left in warm air, which gets colder :)
0.15 kg of ice or water, call it m to save typing
heat to warm ice from -15 to 0
Hwarm =m * 2100 * (0 - -15) = m * 2100 (15)
Hmelt = m * 336,000
Hrise = m * 4200 * (21-0)
add them and then use 0.15 kg for m