500500500500500500

400400400400400400

300300300300300300

200200200200200200

100100100100100100

EquilibriumRate Constant

Integrated Rate Law

Activation Energy

Reaction Mechanisms

Rate Laws

A reaction has the rate law,Rate = k[A][B]2. What is the

overall order for the reaction?

Third Order Overall

Return

A reaction has the rate law, rate = k[A][B]2. If the

concentration of both A and B are doubled, what happens to the rate?

Increases by a factor of 8.

Return

The equation, 2A + 2B C + D, describes an elementary reaction which takes place in a single step. What is the rate law?

Rate = k[A]2[B]2

Return

Based on the following equation, which of the following compounds would you expect to undergo the most change in concentration in a given amount of time?

2NH3 N2 + 3H2

H2

Return

For the reaction, 2XO + O2 2XO2, the following data was obtained. What is the rate law for the reaction?

Trial [XO] [O2] rate 1 0.010 0.010 2.5 2 0.010 0.020 5.0 3 0.030 0.020 45.0

Rate = k [XO]2[O2]Return

The reaction: A + 3B D + F was studied and the following mechanism was determined

A + B ↔ C (fast) C + B D + E (slow) E + B F (very fast)Which step is the rate determining step?

The second step (slow step) Return

Suppose the reaction:

A + B D followed the mechanism

A + B ↔ C (fast)C D (slow)What is the rate law

for the reaction?

Rate = k[A][B]

Return

The reaction A + 3B D + F was followed and the following mechanism was determined:

A + B ↔ C (fast) C + B D + E (slow) E + B F (very fast)Identify the intermediates.

C and E

Return

The reactionA +3B D + F was

studied and the mechanism was determined to be:

A + B ↔ C (fast)C + B D + E (slow)E + B F (very fast)What is the rate law?

Rate = k[A][B]2

Return

The decomposition of H2O2 is determined to occur by the following mechanism:

H2O2 + I- H2O + IO- (slow)H2O2 + IO- H2O + O2 + I- (fast)What is the overall reaction? 2H2O2 H2O + O2

Return

How does a catalyst alter the rate of a chemical reaction?

Lowers the activation energy (provides an alternative pathway)

Return

For a one step reaction, the activation energy for the forward reaction is 40 kJ/mol and the enthalpy of reaction is -20 kJ/mole. Which reaction is slower; the forward or the reverse?

The reverse reaction is slower

Return

According to the collision theory, what two conditions must be met in order for a reaction to occur?

Reactants must possess a minimum amount of energy and the collisions must occur with the correct orientation

Return

How can the slope of a plot of ln(k) vs 1/T for a reaction be used to determine the activation energy?

By multiplying by –R (-8.314) Return

For a one step reaction the activation energy is 40 kJ/mol and the enthalpy of reaction is 20 kJ/mol. What is the activation energy of the reverse reaction?

20 kJ/mol

Return

The following reaction was studied: A B + C. The graph of 1/[A] vs time gave a straight line. What is the order of the reaction with respect to A?

2nd order

Return

Given a reaction, 2A + B P, for which the observed rate law is rate = k [A], what is the integrated rate law?

ln[A] = -kt + ln[A]o

Return

In a first order reaction, what fraction of the material will remain after 4 half lives?

1/16

Return

A first order reaction has a rate constant of 0.00318 min-1. What is the half life of the reaction?

21.8 minutes

Return

A graph of [A] vs time gave a straight line. How does doubling the concentration of A affect the rate of the reaction?

It has no affect

Return

How does changing the concentration affect the rate constant?

It has no affect

Return

How does increasing the temperature affect the rate and the rate constant?

It increases both the rate constant and the rate

Return

What is the unit for the rate constant in a reaction that is 2nd order overall?

L/mol s

Return

In a zero order rate law, what units must the rate concept possess?

Mol/L time Return

A rate constanthas the units s-1.

Doubling the concentration would have what affect on the overall rate of reaction?

It would double the rate

Return

What factors affect the value of Keq?

Temperature and nature of reactants

Return

How does a catalyst affect the value of Keq?

It has no effect

Return

If K>1, what does that indicate about the equilibrium position?

The concentration of products is greater than the concentration of reactants at equilibrium

Return

Increasing the temperature increases the value of Keq. Is the reaction endothermic or endothermic?

endothermic

Return

According to the equation:3H2(g) + N2(g) 2NH3(g),

if the volume of the reaction chamber increases, will the forward or reverse reaction be favored?

Reverse reactionReturn