Question

The latent heat of fusion of alcohol is 50 kcal/kg and its melting point is -54oC. It has a specific heat of 0.60 in its liquid state. Calculate the energy needed to melt 2.0 kg of solid alcohol at -54o and raise it to a temperature of -4°C.

40. kcal
100 kcal
160 kcal
280 kcal

Answer 1

C

Step-by-step explanation:

To melt the alcohol

Heat needed = M . L = 2 . 25 = 50 kcal

To warm up the alcohol

Heat needed = M . sp. ht. . ∆t = 2 . 0.6 . 100 = 120 kcal

Total heat needed = 170 kcal

Assuming that 0.6 kcal/ kg / ˚C is the specific heat and that the answer is wanted in kcal ( a rather odd unit to be in use here.)