[WK95]

Time (min)   Absorbance
5          0.574
10          0.531
15          0.494
20          0.462
25          0.434
30          0.409
35          0.387
40          0.367
45          0.349
50          0.332

Through the use of Excel, I have determined the reaction to be second order. The graph is 1/A vs. t.

For the trend line is y = 0.1406x + 1.4608 while R² = 1.

1.) What is the absorbance of the sample at the time of the mixing of the solution?
The absorbance at time of mixing should be 1/1.4608 since when t=0, 1.4608 is equal to teh y-intercept which is equal to 1/A. Thus 1/A_0=1.4608. Thus, A when t=0, the time or mixing, is equal to 0.685

However, this answer is wrong. I'm not sure why.

2.) What is the rate constant, k, in terms of concentration, for this reaction?
The answer for this is not 0.141 or 1.1406 which is odd since I thought that the rate constant of a second order reaction is equal to the slope of the trendline of the graph of 1/A vs. T.