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1) A reaction was run with two different initial concentrations of reactants A a

ID: 889459 • Letter: 1

Question

1)

A reaction was run with two different initial concentrations of reactants A and B:

Experiment

A / M

B / M

rateB / (M/sec)

1

0.00082

0.00053

0.0737

2

0.00082

0.00228

0.3169

What is the order of the reaction with respect to B?

2)

A reaction was run with two different initial concentrations of reactants A and B:

Experiment

A / M

B / M

rateB / (M/sec)

1

0.00059

0.00064

0.000865

2

0.00059

0.00697

0.1026

What is the order of the reaction with respect to B?

Experiment

A / M

B / M

rateB / (M/sec)

1

0.00082

0.00053

0.0737

2

0.00082

0.00228

0.3169

Explanation / Answer

1) rate equation for the reaction is rate = k [B]n, where n = order with respect to B

0.0737 = k 0.00053n ---------(1)

0.3169 = k 0.00228n --------(2) , Now divide equation (1) by (2)

    0.0737/0.3169 = (0.00053/0.00228)n

0.2325 = (0.2325)n

n = 1 , so first order reaction with respect to B

= k 0.00053 ---------(1)

0.3169 = k 0.00228 --------(2)

    0.0737/0.3169 = (0.00053/0.00228)n

0.2325 = (0.2325)n

n = 1 , so first order reaction with respect to B

2) rate equation for the reaction is rate = k [B]n

0.000865 = k 0.00064n ---------(1)

0.1026 = k 0.00697n --------(2) , Now divide equation (1) by (2)

    0.000865/0.1026 = (0.00064/0.00697)n

0.00843 = (0.09182)n

(0.09182)1/2 = (0.09182)n

n = 1/2 , so order of the reaction with respect to B is 1/2