Question 2.10: Calculate the energy released when (a) 20 g water at 100°C a......

Engineering Thermodynamics [1393131]

Calculate the energy released when (a) 20 g water at 100°C and (b) 10 g of steam at 100°C are each spilt on the hand. Take the specific heat capacity of water to be 4,200 J/kg K and the specific latent heat of vaporisation of water to be 2.2 MJ/kg. Assume that the temperature of the skin is 30°C.

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(a) E = msδT = 0.02 × 4200 × (100 – 30) = 5.88 kJ
(b) E = mL = 0.01 × 2.2 × 10³ = 22 kJ; Total energy released = 27.88 kJ

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