Question

Suppose $0.8$ mole of $NO$ is converted to $N{O}_2$ in the reaction. What amount of heat will be evolved?
$2NO\left(g\right)+O_2\left(g\right)\rightleftharpoons 2N{O}_2\left(g\right)+150kJ$

• A. $30$kJ
• B. $60$kJ
• C. $80$kJ
• D. $130$kJ
• E. $150$kJ

Answer 1

The correct option is B $60$kJ

When 2 moles of $NO$ is converted to ${NO}_2,150kJ$ of heat is evolved

$2\to 150$ $\left(1\right)$

Let's consider that x kj of heat is evolved when 0.8 moles of $NO$ is converted to ${NO}_2$

$0.8\to x$ $\left(2\right)$

From $\left(1\right)and\left(2\right)$

$x=\frac{150\times 0.8}{2}x=60kJ$