Heat Fusion help

Question

When 27.2 g of solid A, at its melting point of 34.0 °C, was added to 62.7 g of liquid A at

51.2 °C, the mixture cooled to 35.0 °C, with no solid remaining. Given the specific heat of

liquid A (s = 0.798 J/g·°C), find the heat of fusion per gram of solid A. Assume that no heat

enters or leaves the mixture. That is, assume that the mixture is an isolated system and

therefore that q1 + q2 + q3 = 0.

Answer 1

Hi Megan,

This is a problem in change of state, and of heat capacity.

For solid a to melt, it had to absorb heat from the liquid. So, that is a function of the amount of solid, and it's heat of fusion. You should have a relationship for that in your course materials (look for heat of fusion and example problems). Likewise, if the liquid transferred heat to melt the solid, the liquid would cool. You should also be able to find a relationship between heat absorbed/released and the change in temperature for a substance. In this case, you will need the heat capacity of the liquid. Overall, the heat removed from the liquid needs to be equal to the heat added to the solid, to melt it.

--Greg