True or False

A catalyst alters the rate of a chemical reaction by:

always providing a surface on which molecules react

changing the products formed in the reaction

inducing an alternate pathway for the reaction with generally lower activation energy

changing the frequency of collisions between molecules

The Rate of a Chemical Reaction

usually is increased when the concentration of one of the reactants is increased

is dependent on temperature

may be inhibited sometimes by certain catalytic agents

will be very rapid if the activation energy is large

For the Reaction
2A --->B + C
which is first order in A and first order overall:

The rate of the reaction will decrease at higher concentrations of B and C.

The time required for one half of A to react is directly proportional to the quantity of A.

The rate of formation of C is twice the rate of reaction of A.

The rate of formation of B is the same as the rate of reaction of A.

A catalyst

takes part in a reaction and speeds it up

appears in the rate equation of a chemical reaction

provides an alternate reaction pathway

raises the activation energy of a reaction

A zero order reaction depends on the concentration ofreactants.

A reaction rate cannot be calculated from the collision frequency alone.

A commonly stated rule of thumb is that reaction rates double for a temperature decrease of about 10 ^oC around room temperature.

If a reaction is first order with a rate constant of 5.48 x 10^-2 sec^-1, how long is required for 3/4 of the initial concentration of reactant to be used up?

The rate constant at 160 ^oC for the first order decomposition of ore is 0.032/min. The half-life of the reaction in seconds is?

A reaction is first order. If its initial rate is 0.0200 M/sec and 25.0 days later its reaction is 6.25 x 10^-4 m/sec, what is its halflife?

For 2NO + O₂ --> 2NO₂ , initial rate data are:

[NO]	0.010	0.010	0.030 M
[O2 ]	0.010	0.020	0.020 M
rate	2.5	5.0	45.0 mM/sec

What is the rate law?

A and B are mixed and the reaction is timed until a color change occurs. The data are:

[A]	0.100	0.050	0.100M
[B]	0.140	0.140	0.070M
time	25 sec	50 sec	100 sec

The order of the reaction in terms of [A] is?

For the reaction 2HgCl₂ + C₂O₄^2- --> products, data are:

[HgCl2 ], M	0.0836	0.0836	0.0418
[C2O42- ] ,M	0.202	0.404	0.404
Init. rate, M/hr	0.26	1.04	0.53

The rate law is?

The correct units of the specific rate constant for a zero-order reaction are?

If the half-life of a reaction depends on the concentration of the reactant, then the reaction cannot be what order?

The reaction has the rate law Rate = k[A][B]². What will happen to the reaction rate when the following change in conditions is performed?

doubling [A]

lowering temperature

tripling [B]

quadrupling [A] and halving [B]

halving [B] and doubling [A]

The reaction 2 H₂ + NO ---> H₂O + 1/2 N₂ is first order in H₂ and second order in NO. The rate law is?

Substance A decomposes by a first-order reaction. Starting initially with [A] = 2.00 M, after 150 min [A] = 0.50 M. For this reaction what is t_1/2 ?

For the above reaction, what is k?

In the first order reaction A ---> products, [A] = 0.400 M initially and 0.250 M after 15.0 min.
What is the value of the rate constant, k?

What is the half-life of the reaction?

At what time will [A] = 0.200 M?

What will [A] be after 175 min.?

The first-order reaction A --> Products has a half-life, t_1/2, of 55.0 min at 25 ^oC and 6.8 min at 100 ^oC. What is the activation energy for this reaction?

The first order reaction A---> products has t_1/2 = 150 sec. What percent of the sample remains unreacted after 300 sec?

The rate constant for a first-order reaction is k = 0.00073 s^-1. Determine the percent of reactant that has decomposed after 500 s.

For the reaction A---> products, the following data are obtained:

First Experiment		Second Experiment
[A] = 1.512 M	t = 0 min	[A] = 3.024 M	t = 0 min
[A] = 1.490 M	t = 1.0 min	[A] = 2.935 M	t = 1.0 min
[A] = 1.469 M	t = 2.0 min	[A] = 2.852 M	t = 2.0 min

What is the initial rate of the reaction in each experiment?

Determine the order of the above reaction.

What is the rate constant, k?

What is the concentration of [A] in the first experiment after 4.0 min?

For a reaction Rate = k[A][B]², how will each factor change k?

raising temperature

increasing [A]

adding catalyst

State the effect of each property on the reaction rate

energy of activation

temperature

catalyst

concentration

Compare and contrast is the main difference between a Pt catalyst and an enzyme catalyst?

Define "Heterogeneous Catalysis"

Define "Rate Law"

Define "Activated Complex"

The rate of a specific chemical reaction is independent of the concentrations of the reactants. What order is the reaction and how can this occur?