Question

Is this right?

Answer 1

4. A calorimeter contains 500 g of water at 25°C. You place a cold pack containing 100 g of crystalline ammonium nitrate inside the calorimeter. When the ammonium nitrate finishes dissolving, the temperature of the water inside the calorimeter is 9.3°C. The specific heat of water is 4.18 J/g–°C. What is the enthalpy of fusion (Hf) of the ammonium nitrate? (Show your work.) Where necessary, use q = mHf.

Answer 2

E= 500*4.18*(9.3-25) = -32813J

Answer 3

Ya that looks good to me!

Answer 4

I think there is some problem with the sign, besides I think it is not enthalpy of fusion but heat of solution or enthalpy of the reaction.
Negative means energy is being releases from the reaction because the final energy is smaller than the initial, so it's exothermic, then the water temperature should rise.
What do you think?