Question

How much heat is required to completely boil away 0.5 kg of ice at -20 degree C?

Answer 1

Answer : Heat required to completely boil away the given ice will be 1.879 x 10⁵ J.

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Solution :

Here we have :

m = 0.5 kg

Initial temperature : T₀ = - 20 ^oC

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Here, Heat required to completely boil away the given ice will be :

Q = m C_ice ΔT + m L_f

Where, C_ice (Specific heat capacity of ice) = 2.04 kJ/kg ^oC

and, L_f (Latent heat of fusion) = 335 kJ/kg.

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Therefore,

Heat required to completely boil away the given ice will be :

Q = (0.5 kg)(2.04 kJ/kg ^oC)(20 ^oC) + (0.5 kg)(335 kJ/kg) = 187.9 kJ = 1.879 x 10⁵ J