A heater of power, P watts, supplies thermal energy to 100g of ice at -8 °C until it fully converts to steam at 100 °C. This heating process took 5.5 minutes. Calculate the value of P.
Specific heat capacity of ice = 2030 J/kg K
Latent heat of fusion of water = 3.36 * 105 J/kg
Specific heat capacity of water = 4200 J/kg K
Latent heat of vaporisation of water = 2.26 * 106 J/kg
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Answer:
Total energy = Pt = ( energy to change ice at -8 °C to ice at 0 °C ) + ( energy to change from 100g of ice to 100g of water ) + ( energy to change from 100g of water at 0 °C to 100g of water at 100 °C ) + ( energy to change from 100g of water to 100g of steam)
Pt = (mcΔθ)ice + (ml)ice + (mcΔθ)water + (ml)water
P * 5.5 * 60 = (0.1 * 2030 * 8) + (0.1 * 336000) + (0.1 * 4200 * 100) + (0.1 * 2260000)
330P = 1624 + 33600 + 42000 + 226000
P = 918.86 W
