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d) Assume that a small, constant amount of HBPB2- consumed in the experiment des

ID: 491522 • Letter: D

Question

d) Assume that a small, constant amount of HBPB2- consumed in the experiment described corresponds to a HBPB2- concentration change of 7.22 x 10-7 M. 1. Calculate the rate constant (at room temperature). 2. What other information do you need to calculate activation energy? 3. Why is it better to transfer one group of solution into one flask and a second group into a second flask and then mix them, instead of pipetting the solutions sequentially into the same flask. 4. For which part of the experiment would it be the most important to keep the flask in the constant-temperature water bath after mixing? What would happen if the temperature of that reaction mixture were not carefully controlled?

Explanation / Answer

with respect to the OH-, by decreasing the OH- concentration by 4, the rate increased by a factor of 4. [OH-]^1/4

with respect to the [HBPB 2-], by decreasing this concentraiton by 2, the rate increased by a factor of 2. [HBPB 2-]^1/2

rate = k x [HBPB 2-]^1/2[OH-]^1/4