Chem1403 ________________________

COOP 3 (name)

 

1.What are the four factors discussed in lecture which influence the rate of a chemical reaction.

 

 

2. Consider the Haber process for the production of ammonia.

 

N2(g) + 3H2(g) --> 2NH3(g)

 

What is the relationship of the production of ammonia to the consumption of hydrogen, answer this both with a word statement, and an algebraic statement.

 

 

3. The thermal decomposition of N2O5(g) to form NO2(g) and O2(g) is a first order reaction. The rate constant for the reaction is 5.1 x 10-4 s-1 at 318 K. What is the half life of the process?

 

 

4. Nitric oxide, NO, reacts with hydrogen to form nitrous oxide, N2O plus water

2NO(g) + H2(g) --> N2O(g) + H2O(g)

 

In a set of experiments the rates of consumption of NO were measured to the following initial concentrations.

 

Initial Rate Initial

of Reaction Concentrations Exp #

of NO_____ NO H2 ________

2.6 x 10-5 M/s 6.4 x 10-3 M 2.2 x 10-3 M 1

1.0 x 10-4 M/s 12.8 x 10-3 M 2.2 x 10-3 M 2

5.1 x 10-5 M/s 6.4 x 10-3 M 4.5 x 10-3 M 3

 

Find the rate law and the value of the rate constant for the reaction of NO

 

 

 

 

5. Radioactive gold-198 is used as the metal in the diagnosis of liver problems. The half-life of this isotope is 2.7 days. If you begin with a 5.6 g sample of the isotope, how much of this sample remains after 8 hours?

 

 

 

6. You are studying the decomposition of ozone dissolved in carbon tetrachloride (CCl4).

2O3 --> 3O2

and want to determine how long it would take a solution to decompose from a concentration of 0.0800M to 0.0300M. You take initial rate data and determine the rate law. Then using that rate law, you use the integrated form to determine the amount of time needed.

 

Exp. # Initial Concentration of O3(M) Initial Rate (M/sec)

1 5.00 x 10-4 6.15 x 10-8

2 2.50 x 10-4 3.06 x 10-8

3 1.25 x 10-4 1.55 x 10-8

 

a. What is the order of reaction with respect to O3? (10 pts)

 

 

 

 

b. What is the value of the rate constant, be sure to include units. (10 pts)

 

 

 

 

c. How long does it take for an initial solution at 0.0800M Ozone (in carbon tetrachloride) to reach a concentration of 0.0300M? (5 pts)

 

 

 

 

7. A reaction has the following rate law: Rate = k[A]2

Which could be a plausible mechanism?

 

a.

 

b.

 

c.

 

d.

 

 

8. A reaction has the following rate law: Rate = k[A]2[B]

Which 2 mechanisms below could be a plausible?

 

a.

 

b.

 

c.

 

d.

 

 

9. Determine the rate constant for a first order reaction of 69% of a sample has decomposed in 37.0 minutes.

 

 

10 Draw two Arrhenius plots for an exothermic reaction. The first without a catalyst, the second with a catalyst. Label all areas of the plots.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

11. The equation for the decomposition of hydrogen peroxide is:

 

2H2O2 2H2O + O2

Addition of potassium iodide to an aqueous hydrogen peroxide solution releases iodide which accelerates the reaction.

 

a. iodide is a homogenous or heterogenous catalyst?

 

b. In the mechanism, Iodide reacts with peroxide to form hypoiodite and water.

Draw a two step mechanism that follows the rate law R=k[H2O2][I-]. Identify any intermediates and catalysts.

 

 

 

 

 

 

 

c. In the mechanism, Iodide reacts with peroxide to form hypoiodite and water.

Draw a two step mechanism that follows the rate law R=k[H2O2]2[I-]. Identify any intermediates and catalysts

 

 

 

 

 

 

 

 

 

 

 

12. The specific rate constant for the formation of HI was measured at two different temperatures. Calculate the numerical values of the activation energy. Calculate the value of the specific rate constant at 400C.

H2 + I2 2 HI

k (1/M-s) Temp (K)

2.710-4 600

3.510-3 650