I'm supposed to calculate the rate equation, including k, for the reaction whose data is given in the table:

Question

Experiment: 1 2 3
Initial Concentration X: 0.10, 0.10, 0.60
Initial Concentration Y: 0.20, 0.10, 0.10
Measured Initial Rate: 2.57, 1.25, 1.27

(I hope the formatting turned out okay)

Here's what I have so far:

When the concentration of X is kept constant and the concentration of Y is doubled (comparing experiment 2 to experiment 1), the rate increases by a factor of 2.056.

When the concentration of Y is kept constant and the concentration of X is multiplied by a factor of 6, the rate increases by a factor of 1.27.

Now I'm not sure what this means for the orders of the reactions. I've only worked with whole numbers so far. Any advice would be greatly appreciated. Once I get those cleared up, I know how to find k.

Thank you!

Answer 1

Ahh never mind, I just remembered logarithms exist . . . oops

Answer 2

OK but be careful. I think changing the (X) by a factor of 6 and the change in rate is only 1.25 to 1.27 this tells me that experimentally there is no change in rate. Also I might be inclined, since this is experimental, to round that 2.06 off to 2.0

Answer 3

So essentially, the order of X is 0 and the order of Y is 1? Which would mean k is equal to 12.85? That seems like a big k, but mathematically it fits.

Answer 4

A couple of thoughts although I didn't do the math for calculating k.
1.
1,27/1.25 = 1.02 and if you do the orders math wise and not "logical" as we've done, you would have 2.06/1.02 = 2.02 which is even easier to use founding as an excuse to get a whole number of 2.0.

2. You might want to calculate k for the three samples you have, then average for a final answer. Also, why do you question 12.5 as being too large? This could be a made up problem for all we know.