Chemical Equilibrium. a) Briefly describe why (or how) it is possible to have an absolute value for the entropy of a system. b) Write appropriate inequalities for Gibbs free energy, Entropy and the Reaction Quotient that determine the direction of spontaneous change for forward, reverse or equilibrium processes. c) Briefly describe what you expect to occur as a function of time at a “single molecule" level for the chemical reaction AB=A +B9) at equilibrium. d) For the case of c how would you determine that the system is not at equilibrium?

Methane and hydrogen sulfide react to form carbon disulfide and hydrogen, like this: CH (g)+2H,S(g) - Cs,(g)+4H, (g) Suppose a mixture of CH, H,S, CS, and H, has come to equilibrium in a closed reaction vessel. Predict what change, if any, the perturbations in the table below will cause in the composition of the mixture in the vessel. Also decide whether the equilibrium shifts to the right or left. dh perturbation change in composition shift in equilibrium to the right The pressure of CH, will O to the left Some CS, is removed. The pressure of H,S will O (none) O to the right The pressure of CH, will O to the left Some H,S is added. The pressure of CS, will O (none) |Privacy Accessibility Check Explanation O 2021 McGraw-Hill Education. All Rights Reserved. Terms of Use Cip 60wa ORAshed plerof

Nitrogen monoxide and water react to form ammonia and oxygen, like this: 4 NO(g)+ 6H,O(g)→ 4 NH3(g)+50,(9) The reaction is endothermic. Suppose a mixture of NO, H,O, NH, and O, has come to equilibrium in a closed reaction vess perturbations in the table below will cause in the composition of the mixture in the vessel. Also decide whether the equilibriL change in composition shift In equilibrium perturbation to the right O to the left The temperature is lowered. The pressure of 02 will O (none) O to the right O to the left ? The temperature is raised. The pressure of NO will O (none)

KINETICS AND EQUILIBRIUM Using Le Chatelier's Principle to predict the result of changing... Nitrogen and hydrogen react to form ammonia, like this: N₂(g) +3 H₂(g) →2NH₂(g) The reaction is exothermic. Suppose a mixture of N₂, H₂ and NH3 has come to equilibrium in a closed reaction vessel. Predict what change, if any, the perturbations in the table below will cause in the composition of the mixture in the vessel. Also decide whether the equilibrium shifts to the right or left. perturbation change in composition The temperature is raised. The pressure of NH3 will ? The temperature is lowered. The pressure of N₂ will ? ? go up. go down. not change. shift in equilibrium to the right to the left O (none) to the right to the left O (none) X 1/5