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Heat of combustion from the temperature rise of a bomb calorimeter

This type of question, asked 4 times: 26 Jul 2022, 27 Jul 2022, 1 Feb 2023, 3 Apr 2025. All 4 questions below, oldest first.

Try each one first, then open its answer.

  1. Question 1

    26 Jul 2022

    54
    2.4 g2.4\ g coal is burnt in a bomb calorimeter in excess of oxygen at 298 K298\ K and 1 atm1\ atm pressure. The temperature of the calorimeter rises from 298 K298\ K to 300 K300\ K. The enthalpy change during the combustion of coal is −x kJ mol−1-x\ kJ\ mol^{-1}. The value of xx is _____. (Nearest Integer) (Given: Heat capacity of bomb calorimeter 20.0 kJ K−120.0\ kJ\ K^{-1}. Assume coal to be pure carbon)

  2. Question 2

    27 Jul 2022

    143
    A gas (Molar mass =280 g mol−1= 280\text{ }g{\text{ }mol}^{- 1} ) was burnt in excess O2O_{2} in a constant volume calorimeter and during combustion the temperature of calorimeter increased from 298.0 K298.0\text{ }K to 298.45 K298.45\text{ }K. If the heat capacity of calorimeter is 2.5 kJ K−12.5\text{ }kJ{\text{ }K}^{- 1} and enthalpy of combustion of gas is 9 kJ mol−19\text{ }kJ{\text{ }mol}^{- 1} then amount of gas burnt is ____\_\_\_\_ g. (Nearest Integer)

  3. Question 3

    1 Feb 2023

    141
     0.3 g\ 0.3\text{ }g of ethane undergoes combustion at 27∘C27^{\circ}C in a bomb calorimeter. The temperature of calorimeter system (including the water) is found to rise by 0.5∘C0.5^{\circ}C. The heat evolved during combustion of ethane at constant pressure is ____\_\_\_\_ kJmol−1kJmol^{- 1}. (Nearest integer) [Given: The heat capacity of the calorimeter system is 20 kJ K−1,R=8.3JK−1 mol−120\text{ }kJ{\text{ }K}^{- 1},R = 8.3JK^{- 1}{\text{ }mol}^{- 1}. Assume ideal gas behaviour. Atomic mass of CC and HH are 12 and 1 g mol−11\text{ }g{\text{ }mol}^{- 1} respectively]

  4. Question 4

    3 Apr 2025

    123
    A sample of n-octane (1.14 g)(1.14\text{ }g) was completely burnt in excess of oxygen in a bomb calorimeter, whose heat capacity is 5 kJ K−15\text{ }kJ{\text{ }K}^{- 1}. As a result of combustion reaction, the temperature of the calorimeter is increased by 5 K . The magnitude of the heat of combustion of octane at constant volume is ____ kJmol−1kJ{mol}^{- 1} (nearest integer).