InterviewSolution
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InterviewSolution
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1 g of graphiteis burnt in a bomb calorimeter in excess of oxygen at 298 K and 1 atmospheric pressure according to the equation C ( graphite ) `+ O_(2)(g) rarr CO_(2)(g)` During the reaction, temperature rises from 298K to 299 K. If the heat capacity ofthe bomb calorimeter is `20.7 kJ // K `, what is the enthalpy change for the above reaction at 298K and 1 atm ? |
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Answer» Rise in temperature of the calorimeter `= 299- 298K = 1K` Heat capacity of the calorimeter `= 20.7 k J K^(-1)` `:. `Heat absorbed by the calorimeter `= C_(v) xxDelta T = (20.7 k J K^(-1)) (1K) = 20.7 kJ` This s the heat evolved in the combustionof1 g of graphite. `:. ` Heat evolved inthe combustionof 1 mole of graphite , `i.e., 12g` of graphite `= 20.7 xx 12 kJ = 248.4 kJ` As this is the heat evolved and the vessel is closed, therefore, enthalpy change of the reaction `( Delta U )` `= - 248.4 kJ mol^(-1)` |
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