The gas-phase equilibrium 2 NOBr(g) ⇌ 2 NO(g) + Br₂(g) is studied at 300 K
CHEMISTRY · Multi-part · A Level · Chemistry · Chemical equilibria (Le Chatelier’s principle and Kc) · Chemical equilibria (Le Chatelier’s principle and Kc)
Problem
The gas-phase equilibrium
2 NOBr(g) ⇌ 2 NO(g) + Br₂(g)
is studied at 300 K, where Kc = 1.8 × 10⁻². A 2.50 L rigid flask at this temperature initially contains 0.200 mol NOBr and 0.0600 mol NO; no Br₂ is present. After sealing, the system is allowed to reach equilibrium.
(a) Taking y as the number of moles of NOBr that decompose after sealing, express the equilibrium molarities of NOBr, NO, and Br₂ in terms of y.
(b) Derive the single algebraic equation in y that results from substituting your expressions from part (a) into the equilibrium-constant expression.
(c) Solve for y and determine the equilibrium molarity of each species.
(d) Calculate the total pressure (in atm) in the flask at equilibrium, assuming ideal-gas behavior.