Dinitrogen tetroxide decomposes according to ₂O₄(g) ⇌ 2 NO₂(g) this reaction at 298 ,K,
CHEMISTRY · Multi-part · A Level · Chemistry · Chemical equilibria (Le Chatelier’s principle and Kc) · Chemical equilibria (Le Chatelier’s principle and Kc)
Problem
Dinitrogen tetroxide decomposes according to
N₂O₄(g) ⇌ 2 NO₂(g)
For this reaction at 298\,K, Kc=0.21. A 1.00\,L reaction vessel at the same temperature is charged with the following initial concentrations:
[N₂O₄]₀ = 0.50\,M
[NO₂]₀ = 0.10\,M
(a) Calculate the value of Qc for the reaction as written. Show all work.
(b) Compare Qc with Kc and determine the direction in which the system will spontaneously shift to reach equilibrium. Justify your answer quantitatively.
(c) Without altering the contents of the vessel, the chemist re-writes the chemical equation in the opposite direction. Calculate the numerical value of the reaction quotient for this reversed reaction, Qc,rev.
(d) Without explicitly calculating a new equilibrium constant, state whether the mixture will shift toward reactants or products when analyzed using the reversed chemical equation. Provide a clear explanation based on your value from part (c).