Question

4. Using the following information, calculate m. 4 M Acetone 1.0 M HCI 0.005 MI, 10 ml H,O 17 mL Time 127 s Reaction 1 13 ml 10 mL Reaction 2 6.5 ml 10 ml 10 ml 23.5 ml 254

Answer 1

I'm guessing m is the reaction order for acetone. The reaction rate is given (in this case) by:

V=k. acetone. HCI". 12

If we consider the times for reaction 1 and 2, we can see that for reaction 1 the time is exactly half than for reaction 2, which means that the rate of reaction 1 is double the rate of reaction 2.

We can calculate the concentration of acetone in both cases using the dilution formula:

C.Vi=C2V

Where 1 and 2 refer to values before and after dilution.

We use this and calculate:

reaction1: Cacetone = 4M 13mL 50mL -= 1.04M

reaction2 : Cacetone = 4M 6.5mL -= 0.52M 50mL

Since the volumes of the other reactants and the final volume is the same in both reactions, we know that their concentrations don't change. We can take advantage of this to propose:

Vi V2 k. (acetone)” [HCI) · [12] k. (acetone) [HC12 [12] acetonel [acetonel2 acetonei v (acetone]2

We know that the rate in 1 is double the rate in 2, so: V₁ = 2 V₂. Our expression is now:

2V2 1.041 " = 2 V2 0.521

So, we have:

2=2

Which means that m = 1.