7. is a mixture of 0.0205 mol no₂(g) and 0.750 mol n₂o₄(g) in a 5.25 l flask at 25 °c at equilibrium? if…

7. is a mixture of 0.0205 mol no₂(g) and 0.750 mol n₂o₄(g) in a 5.25 l flask at 25 °c at equilibrium? if not, in which direction will the reaction proceed?\nn₂o₄(g) ⇌ 2 no₂(g) kₑ = 4.61×10⁻³ at 25 °c.
Answer
Explanation:
Step1: Calculate the initial concentrations
The concentration formula is $c=\frac{n}{V}$. For $NO_2$, $c_{NO_2}=\frac{0.0205\ mol}{5.25\ L}$, and for $N_2O_4$, $c_{N_2O_4}=\frac{0.750\ mol}{5.25\ L}$. $c_{NO_2}=\frac{0.0205}{5.25}\ mol/L\approx0.00391\ mol/L$ $c_{N_2O_4}=\frac{0.750}{5.25}\ mol/L\approx0.143\ mol/L$
Step2: Calculate the reaction - quotient $Q_c$
The expression for the reaction - quotient for the reaction $N_2O_4(g)\rightleftharpoons2NO_2(g)$ is $Q_c=\frac{[NO_2]^2}{[N_2O_4]}$. Substitute the calculated concentrations into the $Q_c$ formula: $Q_c=\frac{(0.00391)^2}{0.143}=\frac{1.53\times10^{-5}}{0.143}\approx1.07\times10^{-4}$
Step3: Compare $Q_c$ and $K_c$
Given $K_c = 4.61\times10^{-3}$. Since $Q_c(1.07\times10^{-4})<K_c(4.61\times10^{-3})$, the reaction will proceed in the forward direction to reach equilibrium.
Answer:
The reaction is not at equilibrium and will proceed in the forward direction.