Consider the reaction of peroxydisulfate ion S2O8 ^2 - with iodide ion (I-) in aqueous solution:
S2O8^2-(aq) + 3I-(aq) 2SO4 ^2-(aq) + I3-(aq)
At a particular temperature the initial rate of disappearance of S2O8^2- varies with reactant concentrations in the following manner:
Experiment [S2O8 2-] (M) [I-] (M) Initial Rate (M/s)
1 0.018 0.036 2.6 × 10-6
2 0.027 0.036 3.9 × 10-6
3 0.036 0.054 7.8 × 10-6
4 0.050 0.072 1.4 × 10-5
(a) Determine the rate law for the reaction and state the units of the rate constant.
(b) What is the average value of the rate constant for the disappearance of S2O8^2- based on the four sets of data?
(c) How is the rate of disappearance of S2O8^2- related to the rate of disappearance of I-?
(d) What is the rate of disappearance of I- when S2O8^2- =0.025M and [I-] = 0.050 M?
This solution offers guidelines on how to solve a numerical problem on kinetics, by showing steps and explanation.
Reaction Kinetics, Rate Laws and Equilibrium
1. The isomerization of cyclopropane to form propene
CH3 - CH CH2CH2
is a first-order reaction. At 760 K, 15 percent of a sample of cyclopropane changes to propene in 6.8 minutes. What is the half-life of cyclopropane at 760 K?
2. Consider the two gaseous equilibria (K1 and K2):
SO2(g) + ½O2(g) SO3(g) K1
2SO3(g) 2SO2(g) + O2(g) K2
The values of the equilibrium constants K1 and K2 are related by ________.
3. The following reactions occur at 500 K. Arrange them in order of increasing tendency to proceed to completion (i.e., least completion greatest completion).
1. 2NOCl 2NO + Cl2 KP = 1.7 x 10-2
2. N2O4 2NO2 KP = 1.5 x 103
3. 2SO3 2SO2 + O2 KP = 1.3 x 10-5
4. 2NO2 2NO + O2 KP = 5.9 x 10-5
4. On analysis, an equilibrium mixture for the reaction
2H2S(g) 2H2(g) + S2(g)
was found to contain 1.0 mol H2S, 4.0 mol H2, and 0.80 mol S2 in a 4.0 L vessel. Calculate the equilibrium constant for this reaction.
5. At 35oC, the equilibrium constant for the following reaction is Kc = 1.6 x 10-5.
2NOCl(g) 2NO(g) + Cl2(g)
An equilibrium mixture was found to have the following concentrations of Cl2 and NOCl:
[Cl2] = 1.2 x 10-2 M; [NOCl] = 2.8 x 10-1 M. Calculate the concentration of NO(g) at equilibrium.
6. For the following reactions the equilibrium constants are defined.
A + 2B C K1
C D + E K2
Then for the reaction
A + 2B D + E Kc
the equilibrium constant must be equal to ________.
7. At 700 K, the reaction
2SO2(g) + O2(g) 2SO3(g)
has an equilibrium constant Kc = 4.3 x 106, and the following concentrations are present:
[SO2] = 0.10 M
[SO3] = 10 M
[O2] = 0.10 M
Is the mixture at equilibrium? If not at equilibrium, in which direction-left to right or right to left- will the reaction occur to reach equilibrium?
8. For the following reaction at equilibrium, which choice gives a change that will shift the position of equilibrium to favor formation of more products?
2NOBr(g) 2NO(g) + Br2(g) Horxn = 30 kJView Full Posting Details