Chemistry 21
Kinetics, A+B, and Equilibrium Review
1. Write the correct equilibrium expression for each of the following.
HCN(s) ↔ H+(aq) + CN-(aq) 2N2(g) + O2(g) ↔ 2N2O(g)
NaCl(s) ↔ Na+(aq) + Cl-(aq) 3Ca2+(aq) + 2PO43-(aq) ↔ Ca3(PO4)2(s)
2. The equilibrium equation for the formation of ammonia is
N2(g) + 3H2(g) ↔ 2NH3(g)
At 200°C the concentrations of nitrogen, hydrogen, and ammonia at equilibrium are measured and found to be [N2] = 2.12; [H2] = 1.75, and [NH3] = 84.3. Calculate Keq at this temperature.
(625)
3. For the rusting of iron initially at equilibrium, predict the shift in the reaction with each perturbation.
3 Fe(s) + 4H2O(g) ↔ Fe3O4(s) + 4H2(g) + heat
Increase the amount of water ______
Decrease the volume by half ______
Remove Fe3O4 as it is formed ______
Add hydrogen to the mixture ______
Increase the temperature ______
4. What is the pH and the pOH for a 0.00156 molar solution of the strong acid HCl?
(pH = 2.807, pOH = 11.193)
5. What is the pH and the pOH for a 0.00156 molar solution of strong base NaOH?
(pH = 11.193, pOH = 2.807)
6. What is the role of the rate-determining step in a reaction mechanism?
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7. A catalyst will increase the overall rate of a chemical reaction. Explain how.
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8. An increase in concentration and surface area are two factors that can be used to increase the rate of a chemical reaction. Explain how.
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9. An exothermic reaction was found to actually slow when the reaction was heated. Explain this observation.
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10. The acid dissociation constant (Ka) is an equilibrium constant for an acid dissolved in water. If this value is calculated and it turns out to be a very large number, what does this indicate about the acid? Explain.
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11. Another very common equilibrium constant is the solubility product constant. What is this and how can it be used?
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12. Describe the major properties of an acid. Of a base?
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