A 1.50 L flask at 298 K is charged with 0.0500 mol of dinitrogen tetroxide,
CHEMISTRY · Multi-part · A Level · Chemistry · Chemical equilibria (Le Chatelier’s principle and Kc) · Chemical equilibria (Le Chatelier’s principle and Kc)
Problem
A 1.50 L flask at 298 K is charged with 0.0500 mol of dinitrogen tetroxide, N2O4(g), and no nitrogen dioxide. The sealed vessel is allowed to reach equilibrium according to
N2O4(g)⇌2NO2(g)
After equilibrium is established, the measured concentration of NO2(g) is 0.0160M. Assume ideal-gas behaviour and constant temperature throughout the experiment.
(a) Write the equilibrium-constant expression Kc for the reaction.
(b) Calculate the equilibrium concentrations of both N2O4(g) and NO2(g) in the flask.
(c) Determine the numerical value of Kc at 298 K for this reaction, including the correct units or stating that it is unitless, as appropriate.
(d) Based on the magnitude of the calculated Kc, explain whether the equilibrium mixture contains a greater proportion of reactants or products and provide one piece of numerical evidence from your calculations to support your claim.