Question

A chemist does a reaction rate analysis on the following reaction:

2CO (g) + O2 (g) → 2CO2 (g)

She collects the following data:

Trial Initial Concentration of

CO (M) Initial Concentration

of O2 (M) Instantaneous

Reaction Rate (M/s)

1 0.150 0.150 0.113

2 0.300 0.150 0.226

3 0.300 0.300 0.904

What is the rate equation for this reaction?

Answer 1

The rate equation is rate = k(CO)^x(O2)^y.
Divide rate 2 by rate 1.
0.226/0.113 = 2 and
2 = (0.300)^x(0.150)^y/(0.150)^x(0.150)^y

Note that 0.150^y cancels with 0.150^y and leaves just
2= (2)^x and x must be 1.
Do the same thing for rate 3 divided by rate 2 and determine y. You should get 2. Then substitute x = 1 and y = 2 into any of the three rate equations to determine k, then write the equation. If you get stuck, post your work in a new post at the top of the page (this post is close to the bottom when I read it) and I can help you through it.