You forgot to post 'the following' .
Answer:
The mixing of two chemicals may result in the production of a gas which is lost to the air. This will reduce the mass of the chemical mixture, because mass is being lost in a gaseous form.
When you want to melt an ice, you only need the latent energy of fusion, <span>δhfus. We use the given value, then multiply this with the given amount to determine the amount of energy. Since the energy is per mole basis, use the molar mass of ice which is 18 g/mol. The solution is as follows:
</span>ΔH = 5.96 kJ/mol * 1 mol/18 g * 500 g
<em>ΔH = 165.56 kJ</em><span>
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If you think of it endothermic is when there is energy needed for the reaction to occur and exothermic is when the reaction releases energy
