The latent heat of fusion of alcohol is 25 kcal/kg and its melting point is -114 o c. 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 -114 o c and raise it to a temperature of -14 o c.
a) 70 kcal
b) 120 kcal
c) 170 kcal
d) 220 kcal

Total energy is 170 kJ

Explanation:

Given data:

latent heat of fusion of alcohol is 25 kcal/kg

melting point of alcohol is -114 degree c

specific heat us 0.60 k cal/kg degree c

energy need for 2 kg solid alcohol is

for Melting:

Energy Q is calculated as

Energy, Q = 25 \times 2.0 kg = 50 kJ

Energy required for Heating liquid:

Energy, ΔH = 2.0 kg \times 0.60 \times (100°C) = 120 kJ

Total  energy = (50 kJ + 120 kJ) = 170 kJ

the correct choice is a .

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