ANSWER ALL QUESTIONS

1. The reaction between C and D is represented as follows:

C + D E

The experiment results are shown in the table below

Exp.

Initial

concentration (M) Time interval

(minutes)

The change in

concentration of C

(M) [C] [D]

1 0.10 1.0 30 2.5 X 10-3

2 0.10 2.0 30 1.0 X 10-2

3 0.05 1.0 120 5.0 X 10-3

i. Calculate the rate of reaction for each experiment <1.389 x 10-6> <5.56 x 10-6> <6.94 x 10-6>

ii. Determine the order of reaction with respect to C and D and

write the rate law

iii. State the effect on the reaction rate if the concentration of D

is doubled but the concentration of C remains constant.

Chemistry Unit

Session 2013/2014

Semester 2

Sample QUIZ Paper

NAME : ________________________________________________

MATRIC NUMBER : ________________________________________________

CLASS : ________________________________________________

NAME OF TUTOR : _____________________________________________

Solution: a) (i) The rate of reaction for each experiment

1) 30

105.2 3x= 8.3 x 10

-5 M/min @ 1.39 x 10

-6 M/s

2) 30

100.1 2x= 3.3 x 10

-4 M/min @ 5.56 x 10

-6 M/s

3) 120

100.5 3x = 4.2 x 10

-5 M/min @ 6.94 x 10

-7 M/s

ii) Rate = k[A]x[B]

y

8.3 x 10-5

= k(0.1)x(1.0)

y …………………..(1)

3.3 x 10-4

= k(0.1)x(2.0)

y……………………(2)

4.2 x 10-5

= k(0.05)x(1.0)

y ………………….(3)

(2) /(1)

4 = (2)y

y = 2

(3)/(1)

0.5 = (0.5)x

x = 1

Rate = k[A]1[B]

2

iii) Reaction rate increases four fold.