This item can be answered using the equation,
h = mcp(dT) + mHv
where h is the heat, m is the mass of the substance, cp is the specific heat, and dT is the temperature difference, Hv is the latent heat of fusion. Substituting the known values from the given above,
551 cal = (5 g)(1 cal/g°C)(T - -20) + (5 g)(80 cal/g)
The value of T from the equation is 10.2.
Answer: 10.2°C