Name ______
CHEMICAL KINETICS AND CHEMICAL EQUILIBRIUM
Assume that R = 8.314Jmol-1K-1
1. For the following reaction mechanism,
(a) write out the overall reaction (2 points)
(b) what is the reactive intermediate? (1 points)
(c) What is the rate law for this reaction in terms of [O3] and [O2] (7 points)
2. Consider the two 1-step elementary reactions, (i) H + I à HI and (ii) NOCl + NOCl à 2NO + Cl2. Let us assume that both reactions have the same activation barrier height, and the same collision frequency factor z. Which reaction would have the fastest rate?
(a) reaction (i)
(b) reaction (ii)
(c) they would have the same rate
In a reaction A + B à C + D you measure the concentration of [A] and [B] as a function of time. You perform 2 experiments, in one [B]o > [A]o so that the time dependent rate only is measuring the rate’s dependence on [A]t. In this experiment you find that when you plot ln[A]t vs time you get a straight line. In the second experiment [A]o > [B]o meaning that the time dependence of the rate only depends on [B]t so and when you plot 1/[B]t versus time you get a straight line. What is the overall order of reaction?
3. What is the order of reaction with respect to [A]?
(a) 0 (b) 1 (c) 2 (d) 3 (e) 4
4. What is the order of reaction with respect to [B]?
(a) 0 (b) 1 (c) 2 (d) 3 (e) 4
5. What is the overall order of reaction?
(a) 0 (b) 1 (c) 2 (d) 3 (e) 4
6. For the general reaction what is the equilibrium constant Kc?
7. What is the equilibrium constant for the following reaction,
8. For which of the following reactions will Kp = Kc?
9. Consider the following reaction:
A reaction mixture at 780oC initially contains [CO]=0.5M and [H2]=1M. At equilibrium the CO concentration is found to be 0.15M. What is the equilibrium constant for the reaction?
(a) 26 (b) 0.385 (c) 3.59 (d) 0.278 (e) 6.67
10. Consider the following reaction . A reaction mixture contains , is the reaction mixture at equilibrium and if not in which direction will it proceed?
(a) yes, will not change
(b) no, will move toward the right
(c) no, will move toward the left.
11. Consider the following reaction of nitrogen and hydrogen to make ammonia occurring inside a piston, equilibrium is established and the concentrations of the reactants and product measured. You then push the piston down to increase the pressure of the gases and decrease the volume, what happens to the equilibrium?
(a) the equilibrium shifts right toward product
(b) the equilibrium shifts left toward reactants
(c) there is no change in the concentration of reactants or products
12. Consider the reaction
the reaction is known to be exothermic. The equilibrium concentrations of the H2, and I2 and HI are measured at 1000K. The temperature of the reaction vessel is changed to 800K. What happens to the reaction equilibrium, does it
(a) shift left
(b) shift right
(c) remain unaffected?
13. Consider the following observations about the reaction
Is this reaction
(a) exothermic, (b) endothermic, (c) neither?
The reaction 2 SO2(g) + O2(g) 2 SO3(g) with ΔH° = -198 kJ at equilibrium. How will each of the following changes affect the equilibrium concentrations of each gas once equilibrium is re-established?
14. Adding more O2 to the container
(a) Equilibrium shifts left
(b) Equilibrium shifts right
(c) Equilibrium remains unchanged
15. Condensing and removing SO3
(a) Equilibrium shifts left
(b) Equilibrium shifts right
(c) Equilibrium remains unchanged
16. Compressing the gases
(a) Equilibrium shifts left
(b) Equilibrium shifts right
(c) Equilibrium remains unchanged
17. Cooling the container
(a) Equilibrium shifts left
(b) Equilibrium shifts right
(c) Equilibrium remains unchanged
18. Doubling the volume of the container
(a) Equilibrium shifts left
(b) Equilibrium shifts right
(c) Equilibrium remains unchanged
19. Warming the mixture
(a) Equilibrium shifts left
(b) Equilibrium shifts right
(c) Equilibrium remains unchanged
20. Adding the inert gas helium to the container
(a) Equilibrium shifts left
(b) Equilibrium shifts right
(c) Equilibrium remains unchanged
21. Adding a catalyst to the mixture
(a) Equilibrium shifts left
(b) Equilibrium shifts right
(c) Equilibrium remains unchanged
22. In a sealed piston the following reaction in conducted , what change will affect the equilibrium constant?
(a) Increasing the amount of CO2(g)
(b) Decreasing the amount of C(s)
(c) Reducing the volume of the reaction vessel by applying pressure to the piston
(d) Increasing the temperature of the reaction
(e) None of the above
23. Consider the following reaction
In an equilibrium mixture [COF2]=0.255M and [CF4]=0.118M what is [CO2]?
(a) 4.32M (b) 1.10M (c) 0.55M (d) 2.16M (e) 1.08M
24. Consider again the reaction . At 25oC the mixture initially contains .
(a) Find the equilibrium partial pressures of I2, Cl2 and ICl at this temperature. (6 points)
(b) what will Kc be at this temperature? (4 points)
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