In a constant volume calorimeter, 3.5 g of a gas with molecular weight 28 was burnt in ress oxygen at 298 K. The temperature of the calorimeter was found to Increase from 298 K to 298.45 K due to the combustion process. Given that the calorimeter constant is 2.5 KJ K^(-1) .Calculate the enthalpy of combustion of the gas in "kJ mol"^(-1).

In a constant volume calorimeter, 3.5 g of a gas with molecular weight

1.	In a constant volume calorimeter, 3.5 g of a gas with molecular weight 28 was burnt in ress oxygen at 298 K. The temperature of the calorimeter was found to Increase from 298 K to 298.45 K due to the combustion process. Given that the calorimeter constant is 2.5 KJ K^(-1) .Calculate the enthalpy of combustion of the gas in "kJ mol"^(-1).
Answer» Solution :Given `T_i`=298 K `T_f` =298.45 K `k=2.5 kJ K^(-1)` m=3.5 g `M_m`=28 heat EVOLVED=`kDeltaT` `=k(T_f-T_i)` `=2.5 kJ K^(-1)(298.45-298)K` =1.125 kJ `DeltaH_C=1.125/3.5xx28 "kJ MOL"^(-1)` `DeltaH_C=9 "kJ mol"^(-1)`