Question

Heat of a reaction is defined as the amount of heat absorbed or evolved at a given temperature when the reactants have combined to form the products is represented by balanced chemical equation. If the heat is denoted by $q$ then the numerical value of $q$ depends on the manner in which
the reaction is performed for two methods of conducting chemical reactions in calorimeters.

The heat capacity of a bomb calorimeter is 300 J/K. When 0.16 gm of methane was burnt in this calorimeter, the temperature rose by $3^{\circ }\text{C}$. The value of $\Delta U$ per mole will be:

• A. 100 kJ
• B. 90 kJ
• C. 900 kJ
• D. 48 kJ

Answer 1

The correct option is B 90 kJ

Given data:
$C=\frac{q}{\Delta T}=300J/K$
Reaction:
$C{H}_4+2O_2\to C{O}_2+2H_{2}O$
foe given mole of methane (0.16/16=0.01) mole
$300=\frac{q}{3}$
$q=900J$
so for one mole of methane
$q=900\times \frac{1}{0.01}=90kJ$