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tensirk
Feb22-11, 09:48 AM
1. The problem statement, all variables and given/known data
The reaction 2NO(g) + O2(g) ---> 2NO2(g) is second order in NO and first order in O2.
When [NO] = 1 M and [O2] = 1.9 M, the observed rate of disappearance of NO is 0.00017670 M/s.

I have already found the value of the rate constant to be 2. I found that the units of the rate constant are M-2s-1. I lastly found that the rate of the reaction would increase if the concentration of NO were increased by a factor of 1.4.

Now I am having a lot of trouble figuring out these last two problems:
1. By what factor would the rate of reaction of NO increase? [if it were increased by a factor of 1.4]
2. What is the rate of reaction when [NO] = 0.1 M and [O2] = 0.19 M?

2. Relevant equations
Honestly, I don't even know where to begin in terms of equations for these two problems.

3. The attempt at a solution
I think where I'm having trouble is understanding what "second order in NO" means. Any guidance on these problems would be MUCH appreciated, as I feel completely lost. Thanks in advance!

Borek
Feb22-11, 10:51 AM
v=k[O2][NO]2

cep
Feb28-11, 08:57 PM
The "orders" are the powers to which the concentrations are raised. These come from the stoichiometric ratios of the reactants.

sjb-2812
Mar1-11, 01:24 AM
The "orders" are the powers to which the concentrations are raised. These come from the stoichiometric ratios of the reactants.

Not necessarily. For instance, the rate of halogenation of acetone is proportional to the concentration of acid, and is independent of the concentration of halogen.