Chemistry Pre-Lab

(1 mark) The following data were collected for a reaction of type:

 

A + B Products 

where [B] was 0.25 M after the reactant solutions were mixed, i.e. a large excess. 

Complete the last three columns: 

Time (s)          [A] (M)                    – [A]         – ln[A]         1/[A] 

0                  1.00 × 10–3

 

5                  6.07 × 10–4                                                                                  

 

10                3.68 × 10–4                                        

 

15                2.23 × 10–4

 

20                1.35 × 10–4

 
 

2. (1 mark) Determine the order of the reaction with respect to A and the value of the pseudo rate constant, keff-1. Your answer must include graphs, drawn neatly by hand on  graph paper or generated by a computer spreadsheet program, as well as a brief  explanation. Freehand sketches of the graphs are not acceptable.  

 
 
 

3. (2 marks) The following data were collected using a concentration [B] = 0.50 M in the reaction mixture. 

 

Time (s)                                 [A] (M)                      third colunm

0                                      1.00 × 10–3

 

5                                      1.35 × 10–4

 

10                                      1.83 × 10–5

 

15                                       2.48 × 10–6

 

20                                       3.36 × 10–7

 
 

Using the appropriate function of concentration as determined in Question 3, complete the  third column in the table, labeling it to indicate which function you used. 

Plot a graph to  determine the new pseudo rate constant, keff-2, and then, by comparing it to the value from 

question 3, calculate the order of the reaction with respect to the reactant, B. 

 
 
 

(1 mark) Calculate the average overall rate constant, k, from the two pseudo rate constants 

from Questions 3 and 4, and write down the complete rate law.