At 350 K the equilibrium constant for the reaction 2 , SO _2(g)+ O _2(g) , ,2 , SO…

CHEMISTRY · Multi-part · A Level · Chemistry · Gaseous equilibria (Kp) · Gaseous equilibria (Kp)

Problem

At 350 K the equilibrium constant

K_p

for the reaction

2\,\text{SO}_2(g)+\text{O}_2(g)\,\rightleftharpoons\,2\,\text{SO}_3(g)

1.3\times10^{15}

. A sealed 1.00 L reaction vessel initially contains only

1.0\times10^{-3}\,\text{mol}

\text{SO}_2

gas and

1.0\times10^{-3}\,\text{mol}

\text{O}_2

gas at 350 K. (1) Without performing a full equilibrium calculation, determine whether the composition at equilibrium will consist predominantly of reactants, predominantly of products, or significant amounts of both. Clearly state your reasoning based on the given

K_p

value. (2) Estimate, to the nearest order of magnitude, the ratio

\dfrac{n_{\text{SO}_3}}{n_{\text{SO}_2}}

that is expected at equilibrium. Show how the magnitude of

K_p

leads to your estimate. (3) Explain why the initial quantities of

\text{SO}_2

and

\text{O}_2

used in this experiment do not change the numerical value of

K_p

, yet do influence the extent to which the reaction appears to "go to completion."

Related theory

Browse the problem library