J.R. S. answered 05/02/20
Ph.D. University Professor with 10+ years Tutoring Experience
You did not provide a reaction that you refer to, so let us assume it is the following:
2 NO2 +F2 ==> 2NO2F
When you reduce NO2 in half from 1 atm to 0.5 atm, but keep F2 constant at 1 atm, the rate is halved from 0.1 atm/sec to 0.05 atm/sec. Thus, the reaction is 1st order in NO2
When you reduce F2 by 4 fold from 1 atm to 0.25 atm but keep NO2 constant at 1 atm, the rate is reduced 4 times from 0.1 atm/sec to 0.025 atm/sec. Thus, the reaction is 1st order in F2.
The rate law is...
rate = k(NO2)1(F2)1
rate = k(PNO2)1(PF2)1
I think you asked this question earlier.