1. I II III I and III II and III 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Suppose a reaction A + B {image} C occurs at some initial rate at 0°C. Which response includes all of the changes below that could decrease the rate of this reaction? I. lowering the temperature II. adding a catalyst III. decreasing the initial concentration of A I II
III
I and III
II and III 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

2. What can be said about the stoichiometric coefficients of a balanced chemical equation for a reaction and the powers to which the concentrations are raised in the rate law expression?
There is an exact relationship between the two.
Not much can be said except that there is no necessary relationship.
The powers can be equal to the number of molecules that are formed.
The powers are equal to the number of molecules that must collide and react in the fastest step.
The powers equal the coefficients of the equation for the reaction at 298 K. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

3. first second third fourth none of these 1 2 3 4 5 6 7 8 9 10 11 12 13
The rate expression for the following reaction is found to be: rate = k[N2O5]. What is the overall reaction order? 2N2O5(g) {image} 4NO2(g) + O2(g)
first
second
third
fourth
none of these 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

4. The units of the rate constant for a first order reaction could be _________.
M-1· min-1 M
M · min-1
min-1
M2 · min-1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

5. increase, 1.69 decrease, 0.19 increase, 1.33 decrease, 1.25
A reaction is first order in X and second order in Y. Tripling the initial concentration of X and cutting the initial concentration of Y to three-fourths of its previous concentration at constant temperature causes the initial rate to _________ by a factor of _________.
increase, 1.69
decrease, 0.19
increase, 1.33
decrease, 1.25
increase, 2.25 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

6. The following rate data apply to the reaction 3X + Y + 2Z {image} Products at a particular temperature. The form of the rate law expression is rate = ____________ . Experiment / Initial [X] / Initial [Y] / Initial [Z] / Initial Rate of Loss of X M / M / M / 6.40 x 10-3 M•min / / / 4.00 x / / / 4.00 x / / / 1.02 x / / / 6.40 x 10-3
k[X][Y][Z]
k[X]3[Y][Z]2
k[X]2[Z]
k[X][Y]2
k[Z]2 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

7. The oxidation of NO by O3 is first order in each of the reactants, and its rate constant is 1.5 x 107 M-1 · s-1. If the concentration of NO is 1.0 x 10-7 M and the concentration of O3 is 2.0 x 10-7 M , what is the rate of reduction of O3 in M · s-1?
3.0 x 10-6
2.5 x 10-14
7.5 x 10-7
3.0 x 106
3.0 x 10-7 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

8. The gas phase reaction 3C + 2D {image} E + F obeys the rate-law expression rate = k[D] and has a half-life of s. If 2.00 mole of D is injected into a 1.00-L container with excess C, what concentration of D remains after 1.50 seconds?
0.48 M
0.60 M
1.68 M
1.40 M
1.06 M 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

9. Given the following potential energy diagram for the one-step reaction X + Y {image} Z + R The reaction ___________. {image}
releases energy
absorbs energy
is impossible
occurs without a net change in energy
may either absorb or release energy 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

10. The reaction A + B {image} C + D, obeys the rate law expression rate =k[A][B]. Which response lists all the proposed mechanisms below that are consistent with this information and none that are inconsistent? I. A + B {image} C + D one step II. A + B {image} E fast, equilibrium E {image} C + D slow III. A + B {image} E fast, equilibrium A + E {image} C + B slow
I and II II
III
II and III
I, II, and III 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

11. The principal reason for the increase in reaction rate with increasing temperature is
molecules collide more frequently at high temperatures.
the pressure exerted by reactant molecules increases with increasing temperature.
the activation energy increases with increasing temperature.
the fraction of high energy molecules increases with increasing temperature.
the activation energy for the forward reaction decreases while the activation energy for the reverse reaction increases. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

12. 63.8 kJ/mol 75.1 kJ/mol 8.12 kJ/mol 52.9 kJ/mol 68.3 J/mol
What would be the activation energy of a reaction if its rate constant at 35°C was double the value of its rate constant at 25°C?
63.8 kJ/mol
75.1 kJ/mol
8.12 kJ/mol
52.9 kJ/mol
68.3 J/mol 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

13. another one or another combination
Which response includes all the true statements and no false statements? A catalyst can ___________ I. make a nonspontaneous reaction spontaneous II. speed up a forward reaction and slow down the reverse reaction III. lower the activation energy of the forward reaction IV. lower the activation energy of the reverse reaction
I and III
II and III
I and IV
III and IV
another one or another combination 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

14. Which statement concerning enzymes is true?
Enzyme catalyze first-order reactions the only.
Enzyme catalyze second-order reactions the only.
Each enzyme catalyzes many different reactions in a living system.
Enzymes are proteins that act as catalysts for specific biochemical reactions.
Nitrogenase is as effective catalyst as iron in production of NH3. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50