# Find the amount of heat required to melt 400 gram ice taken at –20 degrees Celsius. The specific heat of melting

Find the amount of heat required to melt 400 gram ice taken at –20 degrees Celsius. The specific heat of melting of ice is 3.4 * 10 ^ 5 J / kg, the specific heat of ice is 2100 J / (kg C). Find the amount of heat required to vaporize 2 kilograms of water taken at 50 degrees Celsius. Specific heat of water 4200 J / (kg C), specific heat of vaporization 2.3 * 10 ^ 6 J / kg,

m = 400 grams = 0.4 kilograms;

T = -20 degrees Celsius;

q = 3.4 * 10 ^ 5 J / kg;

c = 2100 J / (kg * s).

T2 = 0 degrees Celsius.

It is required to determine Q.

Q = Q1 + Q2 = q * m + c * m * (T2 – T1) = 3.4 * 10 ^ 5 * 0.4 + 2100 * 0.4 * 20 = 1.36 * 10 ^ 5 + 16800 = 136000 + 16800 = 152800 Joules.

Answer: You need energy equal to 152800 Joules.

m = 2 kilograms;

T = 50 degrees Celsius;

q = 2.3 * 10 ^ 6 J / kg;

c = 4200 J / (kg * s).

T2 = 100 degrees Celsius.

It is required to determine Q.

Q = Q1 + Q2 = q * m + c * m * (T2 – T1) = 2.3 * 10 ^ 6 * 2 + 4200 * 2 * 50 = 4.6 * 10 ^ 6 + 420,000 = 4600000 + 420,000 = 5020000 = 5 MJ.

Answer: you need energy equal to 5 MJ.

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