Question

The amount of energy released on complete combustion of $1250g$ of coal, if its calorific value is $30kJ/g,$ is

• A.
  $37.5\times {10}^{6}J$
• B.
  $37.5\times {10}^{3}J$
• C.
  $150kJ$
• D.
  $900kJ$

Answer 1

The correct option is A

$37.5\times {10}^{6}J$
Mass of coal, m = 1250 g

Calorific value $=30kJ/g=30\times {10}^{3}J/gCalorificvalue=\frac{E}{m}\Rightarrow E=m\times Calorificvalue\Rightarrow E=1250\times 30\times {10}^{3}J=37.5\times {10}^{6}J$

Hence, the correct answer is option (a).