Question

How much energy is required to heat 1.5 kg of frozen water from -10

Answer 1

heat required to raise the temperature from -10 C to 0 is given as ::

Q₁ = m c (T_f - T_i)

T_f = final temperature = 0              , T_i = initial temperature = -10

c = specific heat of ice = 2093 J/kg C     , m = mass of ice = 1.5 kg

inserting the values ::

Q₁ = 1.5 x 2093 x (0 - (-10))

Q₁ = 31395 J

heat required to melt ice at 0 C to water at 0 C :

Q₂ = mL            L = latent heat of melting of ice to water = 334 x 10³ J /kg

Q₂ = 1.5 x 334000 J = 501000 J

heat required to raise the temperature of water from 0 C to 100 C is given as ::

Q₃ = m c (T_f - T_i)

T_f = final temperature = 100              , T_i = initial temperature = 0

c = specific heat of water = 4180 J/kg C     , m = mass of water = 1.5 kg

inserting the values ::

Q₃ = 1.5 x 4180 x (100 - 0)

Q₃ = 627000 J

heat required to vapourise water at 100 C to steam at 100 c :

Q₄ = mL            L = latent heat of melting of ice to water = 2257000 J /kg

Q₄ = 1.5 x 2257000 J = 3385500 J

heat required to raise the temperature of steam from 100 C to 150 C is given as ::

Q₅ = m c (T_f - T_i)

T_f = final temperature = 150              , T_i = initial temperature = 100

c = specific heat of steam = 2010 J/kg C     , m = mass of water = 1.5 kg

inserting the values ::

Q₅ = 1.5 x 2010 x (150 - 100)

Q₅ = 150750 J

Total energy = Q₁ + Q₂ + Q₃ + Q₄ + Q₄ = 31395 + 501000 + 627000 + 3385500 + 150750 = 4695645 J