Thermochemistry - JEE Advanced Previous Year Questions with Solutions

Q. In a constant volume calorimeter, 3.5 g of a gas with molecular weight 28 was burnt in excess oxygen at 298.0 K. The temperature of the calorimeter was found to increase from 298.0 K to 298.45 K due to the combustion process. Given that the heat capacity of the calorimeter is 2.5 kJ $\mathrm{K}^{-1}$, the numerical value for the enthalpy of combustion of the gas in kJ $\mathrm{mol}^{-1}$ is [JEE 2009]

Q. Using the data provided, calculate the multiple bond energy $\left(\mathrm{kJ} \operatorname{mol}^{-1}\right)$ of a C C bond in $\mathrm{C}_{2} \mathrm{H}_{2}$. That energy is (take the bond energy of a C–H bond as 350 kJ $\left.\mathrm{mol}^{-1} .\right)$ (A) 1165 (B) 837 (C) 865 (D) 815 [JEE 2012]