Question

An empty 1.0 L was filled with 5.0 moles of oxygen and 4.0 moles of nitrogen monoxide. If the amount of NO₂ at equilibrium is 1.5 moles, calculate the equilibrium constant, Kc.

 

2NO(g)  + O₂(g)     ⇌     2 NO₂ (g)           

 

Answer 1

$K_c=\frac{[NO_2]^2}{[NO]^2[O_2]}$

$\begin{matrix} & 2NO_{g}&+&O_{2(g)}&\rightleftharpoons&2NO_2\\I&4&&5&&0 \\C&-1.5&&-0.75&&1.5\\E&2.5&&4.25&&1.5 \end{matrix}$

$K_c=\frac{1.5^2}{(4.25)(2.5)^2}=0.084706$