Rate Law Extra Questions
1. In studying the kinetics of the reaction  X(g) + Y(g) Z(g)  at 800 K, the data in the following table were observed.
a) Write the rate law for this reaction.
b) What is the numerical value of the specific rate constant.
c) What would be the initial rate of Z formation starting with 0.15 M of X and 0.15 M of Y?
d) How would the rate in c) be changed if, after the reaction had just begun, the volume of the container was abruptly doubled?
Initial Concentrations         Initial Rates
[X] (mol/L)  [Y] (mol/L)    moles/minute
    0.10           0.10               0.030
    0.20           0.20               0.240
    0.30           0.10               0.810
    0.10           0.20               0.120
2. 'A' reacts with 'B' in a one-step reaction to give 'C'. The rate constant for the reaction is 2.0 x 10-3 M-1 sec-1. If 0.50 mole of A and 0.30 mol of B are placed in a 0.50 litre vessel, what is the initial rate of the reaction?
3. Assume that a molecule called A reacts with 2 B molecules in a one-step to give AB2.
a) Write a rate law for this reaction.
b) If the initial rate of formation of AB2 is 2.0 x 10-5 M/s and the initial concentrations of A and B are 0.30 M, what is the value of the specific rate constant?
4. a) Given the following data, determine the rate equation.

Initial Concentration (mol/L)     Initial Rate of Formation
   [O2(g)]     [NO(g)]                      mol/L sec
   0.0010        0.0010                       7.10
   0.0040        0.0010                     28.30
   0.0040        0.0030                   255.60

b) When the concentrations of the substances are as follows determine the rate of the reaction.
[NO] = 0.080 mol/L & [O2] = 0.004 mol/L
c) Write a complete chemical equation for this reaction.

5. A mixture of natural gas and air does not react appreciably at room temperature. When a piece of platinum metal is inserted into the mixture an explosion follows. Why?
6. If you wish to dissolve a lump of sugar in water, how might you increase the rate at which the sugar dissolves. Explain why each procedure you use is effective.
7. Use the Kinetic Molecular Theory to explain why reaction rates vary with temperature.
8. Consider the following reaction mechanism:
A + 2 B ----->  2 Z   (slow)
2 Z + B ------>  2 K + N ( fast)
K + A------> 2 X   (fast)
K + 2 X ------> 2 Q  (fast)

a) Write the overall chemical equation for the reaction represented by this mechanism.
b) Write the rate expression for this reaction.
c) What effect would increasing the concentration of each of the following reagents have on the overall rate of reaction?
     i) increase [A]
    ii) increase [B]
   iii) increase [C]
Discuss each effect separately.

9. List the factors which would affect the rate of a reaction.
10. The following reactions are both exothermic:
a) AC + D2 ---> AD + CD
b) G2 + H2 --> 2 GH
Reaction (a) has a higher activation energy and a higher heat of reaction than reaction (b). On the same graph sketch the energy diagrams of these systems.
11. In the reaction M2 + Q2 -----> 2 MQ, the molecules M:M and Q:Q react chemically by a mechanism that involves the dissociation of the M:M to M atoms by the absorption of light energy. Write a series of equations describing this chain reaction.
12. The combustion of H2 in O2 is a chain reaction much like that of H2 in Cl2. It involves, however, "free radicals" (i.e., molecular species with one unpaired electron) in addition to free H and O atoms. The free radical that have been implicated are the HO and HO2 radicals. Remembering that simultaneous three-particle collisions in the gas phase are so improbable as to be insignificant, write a chain of reaction for the H2O2 reaction similar to that for H2 + Cl2.

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