Please see images for question. Also attached is the recorded data from the expe

Question

Please see images for question. Also attached is the recorded data from the experiment, which may be necessary to answer the question.

Other information: Upon graphing each column (time vs absorbance, time vs ln absorbance, time vs 1/absorbance), the graph of time vs ln absorbance indicates a first order reaction, since it was the only linear graph.

p.s.- I'm reposting the same question I've already posted, because I did not get a very clear answer to the question. The question is asking what is the half--life of the reaction, based on the data provided.

11 Analyze the data graphically to decide if the reaction is zero, first, or second order with respect to crystal violet. graph is the reaction is order, First order: To see if the reaction is first order, it is necessary to plot of the natural logarithm (In A) of absorbance vs. time. Ifthis plot is linear, the reaction is first order. Second Order: To see ifthe reaction is second order, plot a graph of the reciprocal of absorbance vs. time. Ifthis plot is linear, the reaction is second order. Time (Minutes) A 1/A In A 3.0 4.0 2,793 5S8 5.0 3, ISB 6.0 7.0 I 40S 4.2,29 asl 8.0 09 9.0 -1.242 175 10.0 I. Go4 49 11.0 a 040 130 12.0 12 2.189 8.9 29 13.0 2.243 0.419 14.0 12.048 15.0 16.0 0.813 17.0 OS 2. a. 18.0 04 S 22.222 19.0 20.0 032. 3.442 31.2 S

Explanation / Answer

Half life of a reaction is the time it takes to react half the concentration you started with. For example , If you start a chemical reaction with 1mg of a compound and after 10 mins you observe that the concentration has now reduced to 0.5 mg. This means that the half life of the reaction is 10 mins.

Now, regarding your data : Absorbance is directly proportional to concentration which menas that greater the concentration greater will be the value of absorbance.

Lets take the 1st point when t=3 min and A = 0.396. when the concentration is decreased to half of its initial value, absorbance will also decrease to its original value.

reduced absorbance = A/2 = 0.396 = 0.198

This means that when the absorbance value is nearly 0.198, you know that one half life has passes. Look at the value at t= 8 min. The absorbance value at this point is 0.199.

So, from t= 3 min to t= 8 min one half life has passes.

Half life of the reaction = 8min-3min = 5min

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