Reference no: EM131515991

Question 1. Among the solubility rules previously discussed is the statement: Carbonates, phosphates, borates, and arsenates-except those of the ammonium ion and the alkali metals-are insoluble.

(a) Write the expression for the equilibrium constant for the reaction represented by the equation CaCO₃(s) ? Ca²⁺(aq) + CO₃^-(aq).

Is K_c> 1, < 1, or ≈ 1? Explain your answer.

Question 2. Write the mathematical expression for the reaction quotient, Qc, for each of the following reactions:

(a) N₂(g) + 3H₂(g) ? 2NH₃(g)
(b) 4NH₃(g) + 5O₂(g) ? 4NO(g) + 6H₂O(g)
(c) N₂O₄(g) ? 2NO₂(g)
(d) CO₂(g) + H₂(g) ? CO(g) + H₂O(g)
(e) NH₄Cl(s) ? NH₃(g) + HCl(g)
(f) 2Pb(NO₃₎2(s) ? 2PbO(s) + 4NO₂(g) + O₂(g)
(g) 2H₂(g) + O₂(g) ? 2H₂O(l)
(h) S₈(g) ? 8S(g)

Question 3. Write the expression of the reaction quotient for the ionization of HOCN in water.

Question 4. Suggest four ways in which the concentration of PH₃ could be increased in an equilibrium described by the following equation: P₄(g) + 6H₂(g) ? 4PH₃(g) ΔH = 110.5 kJ

Question 5. Pure iron metal can be produced by the reduction of iron(III) oxide with hydrogen gas.

(a) Write the expression for the equilibrium constant (Kc) for the reversible reaction Fe₂O₃(s) + 3H₂(g) ? 2Fe(s) + 3H₂O(g) ΔH = 98.7 kJ

(b) What will happen to the concentration of each reactant and product at equilibrium if more Fe is added?

(c) What will happen to the concentration of each reactant an product at equilibrium if H₂O is removed?

(d) What will happen to the concentration of each reactant and product at equilibrium if H₂ is added?

(e) What will happen to the concentration of each reactant and product at equilibrium if the pressure on the system is increased by reducing the volume of the reaction vessel?

(f) What will happen to the concentration of each reactant and product at equilibrium if the temperature of the system is increased?

Question 6. Hydrogen is prepared commercially by the reaction of methane and water vapor at elevated temperatures. CH₄(g) + H₂O(g) ? 3H₂(g) + CO(g) What is the equilibrium constant for the reaction if a mixture at equilibrium contains gases with the following concentrations: CH₄, 0.126 M; H₂O, 0.242 M; CO, 0.126 M; H₂ 1.15 M, at a temperature of 760 °C?

Question 7. Calculate the number of moles of HI that are at equilibrium with 1.25 mol of H₂ and 1.25 mol of I₂ in a 5.00-L flask at 448 °C. H₂ +I₂? 2HI Kc = 50.2at448°C

Question 8. Assume that the change in concentration of COCl₂ is small enough to be neglected in the following problem.

(a) Calculate the equilibrium concentration of all species in an equilibrium mixture that results from the decomposition of COCl₂ with an initial concentration of 0.3166 M. COCl₂(g) ? CO(g) + Cl₂(g) K_c = 2.2 × 10^-10

(b) Show that the change is small enough to be neglected.