A steam engin intakes 100g of steam at `100^((0))C` per minute and cools it down to `20^((0))C`. Calculate the heat rejected by the steam engine per minute. Latent heart of vaporization of steam `=540 cal g^(-1)`.

Explanation

Heat rejected during the condensation of steam in one minute
`=(100 g)xx(540 cal g^(-1)=5.4xx10^(-4) cal`.
Heat rejected during the cooling of water
`=(100 g)xx(1 cal g^(-1)(0)C^(-1))(100(0)C-20(0)C)`
`=8000 cal`.
Thus, heat rejected by the engine per minute
`=5.4xx10^(4) cal+0.8xx10^(4) cal`
`=6.2xx10^(4)cal`.