Question

 400 g of water at 80°C is mixed with 1 kg of water at 20°C. If the sp. heat cap. of water is 4200 J/kgK, find the final temperature of the mixture.

Answer 1

Let the final temperature of the mixture be 8°C.

Heat lost by hot water = Heat gained by oold water

0.4 x C x (80 - θ) = 1 x C x (θ - 20)

or, 32 - 0.48 = θ - 20

or, θ = 37.14°C