Ammonia is synthesized according to at 298 K A rigid 5.00 L reaction vessel at 298 K…

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

Problem

Ammonia is synthesized according to N2(g)+3 H2(g)⇌2 NH3(g)\mathrm{N_2(g)} + 3\,\mathrm{H_2(g)} \rightleftharpoons 2\,\mathrm{NH_3(g)} Kp=4.3×10−5K_p = 4.3\times10^{-5} at 298 K A rigid 5.00 L reaction vessel at 298 K initially contains the system at equilibrium with partial pressures PN2=1.00 atmP_{\mathrm{N_2}} = 1.00\,\text{atm}, PH2=3.00 atmP_{\mathrm{H_2}} = 3.00\,\text{atm}, PNH3=3.40×10−2 atmP_{\mathrm{NH_3}} = 3.40\times10^{-2}\,\text{atm}. The vessel volume is then suddenly halved to 2.50 L by pushing a piston inward at constant temperature. (1) Calculate the reaction quotient QpQ_p immediately after the compression. (2) Compare QpQ_p with KpK_p and state the direction in which the reaction will proceed to re-establish equilibrium. Explain your reasoning in terms of the change in total pressure and mole ratio of gaseous species. (3) Derive the expressions necessary to compute the new equilibrium partial pressures of N2\mathrm{N_2}, H2\mathrm{H_2}, and NH3\mathrm{NH_3}, and solve for their values. (4) Determine the total pressure in the vessel once the new equilibrium has been attained.

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