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The heat produced on complete combustion...

The heat produced on complete combustion of 20 g of a fuel could raise the temperature of 1.5 kg of water form `25^(@)C` to `75^(@)C`. Calculate the calorific value of the fuel if the specific heat capacity of water is `4.2 J g^(-1).^(@)C^(-1)`. Assume that the heat absorbed by the container is negligible.

Text Solution

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(i) Formula for calorfic value, Q=`msDeltatheta`.
(ii) Find the amount of heat energy required to increases the temperature of 1.5 `mug` of water from `25^(@)C` to `75^(@)C` using the formula Q=ms ...(i)
Let 's' denote specific heat capacity of water and `'Delta theta'` denote change in the temperature. Is this heat energy released due to complete combustion of 20 g of a fuel ?
Then, the formula related to combustion of fuel is Q=m.k. ....(2)
Q=m.k =mwst, since heat released in combustion is absorbed by water. Thus, find the value of 'k'
(iii) `15.75 kJ g^(-1)`
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