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CHM 112
Section 1

Homework Assignment #2
Due January 27, 2006 by 8:05 a.m.

Practice (not to be turned in): 13.1, 13.2, 13.23.



Consider the reaction:

[Co(NH3)5Cl]2+(aq) + [Co(CN)5]3–(aq) [Co(CN)5Cl]3–(aq) + Co2+(aq) + 5 NH3(aq)

The initial concentration of each reactant is equal to the eighth and ninth digits of your Student ID Number divided by 105 M = Cinit. At some temperature, after 12 s, the concentrations of each reactant are reduced to 0.93×Cinit.

  1. What is the average rate of reaction for the first 12 s in terms of the loss of [Co(CN)5]3–?

  2. Based on the definition of a rate, Rate = (0.93×Cinit – Cinit)/(12 – 0)

  3. What is the average rate of reaction for the first 12 s in terms of the gain of NH3?

  4. The stoichiometric ration between ammonia and the cobalt anion is 5:1, so the rate with respect to ammonia will be 5 times the rate with respect to [Co(CN)5]3–

  5. The rate law at 25 oC is found to be Rate = k[Co(NH3)5Cl2+] [Co(CN)53–] with k=5×107 M–1s–1. What is the initial rate at 25 oC?

  6. Rate = (5×107)[Cinit][Cinit]



Specific Answers:

Student ID Number

initial reactant concentrations = Cinit

rate of loss of [Co(CN5)]3– mol/L/s

rate of gain of NH3 mol/L/s

Initial rate at 25 oC mol/L/s

100006330

3.0×10–4

1.8×10–6

8.7×10–6

4.5

100008852

5.2×10–4

3.0×10–6

1.5×10–5

14

100009388

8.8×10–4

5.1×10–6

2.6×10–5

39

100010785

8.5×10–4

5.0×10–6

2.5×10–5

36

100017560

6.0×10–4

3.5×10–6

1.8×10–5

18

100046288

8.8×10–4

5.1×10–6

2.6×10–5

39

100064823

2.3×10–4

1.3×10–6

6.7×10–6

2.6

100077590

9.0×10–4

5.2×10–6

2.6×10–5

41

100105142

4.2×10–4

2.5×10–6

1.2×10–5

8.8

100143544

4.4×10–4

2.6×10–6

1.3×10–5

9.7

100148294

9.4×10–4

5.5×10–6

2.7×10–5

44

100164496

9.6×10–4

5.6×10–6

2.8×10–5

46

100168422

2.2×10–4

1.3×10–6

6.4×10–6

2.4

100170841

4.1×10–4

2.4×10–6

1.2×10–5

8.4

100173015

1.5×10–4

8.7×10–7

4.4×10–6

1.1

100173947

4.7×10–4

2.7×10–6

1.4×10–5

11

100175807

7.0×10–5

4.1×10–7

2.0×10–6

0.25

100176275

7.5×10–4

4.4×10–6

2.2×10–5

28

100180084

8.4×10–4

4.9×10–6

2.5×10–5

35

100180208

8.0×10–5

4.7×10–7

2.3×10–6

0.32

100187549

4.9×10–4

2.9×10–6

1.4×10–5

12

100188349

4.9×10–4

2.9×10–6

1.4×10–5

12

100192352

5.2×10–4

3.0×10–6

1.5×10–5

14

100193608

8.0×10–5

4.7×10–7

2.3×10–6

0.32

100193957

5.7×10–4

3.3×10–6

1.7×10–5

16

100194186

8.6×10–4

5.0×10–6

2.5×10–5

37

100194417

1.7×10–4

9.9×10–7

5.0×10–6

1.4

100195646

4.6×10–4

2.7×10–6

1.3×10–5

11

100196467

6.7×10–4

3.9×10–6

2.0×10–5

22

100197351

5.1×10–4

3.0×10–6

1.5×10–5

13

100197396

9.6×10–4

5.6×10–6

2.8×10–5

46

100200053

5.3×10–4

3.1×10–6

1.5×10–5

14

100201157

5.7×10–4

3.3×10–6

1.7×10–5

16

100203271

7.1×10–4

4.1×10–6

2.1×10–5

25

100205446

4.6×10–4

2.7×10–6

1.3×10–5

11

100205601

1.0×10–5

5.8×10–8

2.9×10–7

0.0050

100207237

3.7×10–4

2.2×10–6

1.1×10–5

6.8

100210303

3.0×10–5

1.8×10–7

8.8×10–7

0.045

100212014

1.4×10–4

8.2×10–7

4.1×10–6

1.0

100212080

8.0×10–4

4.7×10–6

2.3×10–5

32

100212092

9.2×10–4

5.4×10–6

2.7×10–5

42

100212152

5.2×10–4

3.0×10–6

1.5×10–5

14

100212510

1.0×10–4

5.8×10–7

2.9×10–6

0.50

100213402

2.0×10–5

1.2×10–7

5.8×10–7

0.020

100214888

8.8×10–4

5.1×10–6

2.6×10–5

39

100215062

6.2×10–4

3.6×10–6

1.8×10–5

19

100215125

2.5×10–4

1.5×10–6

7.3×10–6

3.1

100215264

6.4×10–4

3.7×10–6

1.9×10–5

20

100215471

7.1×10–4

4.1×10–6

2.1×10–5

25

100216695

9.5×10–4

5.5×10–6

2.8×10–5

45

100216822

2.2×10–4

1.3×10–6

6.4×10–6

2.4

100217841

4.1×10–4

2.4×10–6

1.2×10–5

8.4

100218709

9.0×10–5

5.2×10–7

2.6×10–6

0.41

100218865

6.5×10–4

3.8×10–6

1.9×10–5

21

100218867

6.7×10–4

3.9×10–6

2.0×10–5

22

100218981

8.1×10–4

4.7×10–6

2.4×10–5

33

100219014

1.4×10–4

8.2×10–7

4.1×10–6

1.0

100219019

1.9×10–4

1.1×10–6

5.5×10–6

1.8

100219138

3.8×10–4

2.2×10–6

1.1×10–5

7.2

100219323

2.3×10–4

1.3×10–6

6.7×10–6

2.6

100219636

3.6×10–4

2.1×10–6

1.1×10–5

6.5

100219715

1.5×10–4

8.7×10–7

4.4×10–6

1.1

100219950

5.0×10–4

2.9×10–6

1.5×10–5

13

100220082

8.2×10–4

4.8×10–6

2.4×10–5

34

100220712

1.2×10–4

7.0×10–7

3.5×10–6

0.72

100220848

4.8×10–4

2.8×10–6

1.4×10–5

12

100220947

4.7×10–4

2.7×10–6

1.4×10–5

11

100221065

6.5×10–4

3.8×10–6

1.9×10–5

21

100221836

3.6×10–4

2.1×10–6

1.1×10–5

6.5

100222238

3.8×10–4

2.2×10–6

1.1×10–5

7.2

100222876

7.6×10–4

4.4×10–6

2.2×10–5

29

100223382

8.2×10–4

4.8×10–6

2.4×10–5

34

100223879

7.9×10–4

4.6×10–6

2.3×10–5

31

100224279

7.9×10–4

4.6×10–6

2.3×10–5

31

100224930

3.0×10–4

1.8×10–6

8.7×10–6

4.5

100226239

3.9×10–4

2.3×10–6

1.1×10–5

7.6

100229080

8.0×10–4

4.7×10–6

2.3×10–5

32

100229858

5.8×10–4

3.4×10–6

1.7×10–5

17