Question

Calculate the total amount of heat energy required to convert 100 g of ice at −10℃ completely into water at 100℃. Specific heat capacity of ice = 2.1 J g^-1 K^-1, specific heat capacity of water = 4.2 J g^-1K^-1, specific latent heat of ice = 336 J g^-1.

Answer 1

Initial temperature = -10°C

Final temperature = 100°C

Total heat required to convert 100 g of ice at -10°C to water at 100°C,

Q = mC_i T + mL_i + mC_W T + mL_S

= 100 [2.1 × (0 - (-10)] + 336 + {4.2 × (100 - 0)}

= 100 `[(21/10 xx 10) + 336 + (42/10 xx 100)]`

= 100 [21 + 336 + 420]

= 100 × 777

= 7.77 × 10⁴ J