In: Chemistry
The rate constant for a certain reaction is k = 1.90×10−3 s−1 . If the initial reactant concentration was 0.850 M, what will the concentration be after 15.0 minutes? A zero-order reaction has a constant rate of 2.80×10−4 M/s. If after 75.0 seconds the concentration has dropped to 9.00×10−2 M, what was the initial concentration?
A zero-order reaction has a constant rate of 2.80×10−4M/s. If after 75.0 seconds the concentration has dropped to 9.00×10−2M, what was the initial concentration?
K = 2.303/t log[A0]/[A]
K = 1.9*10^-3sec^-1
[A0] = 0.85M
t = 15minutes = 15*60 900sec
K = 2.303/t log[A0]/[A]
1.9*10^-3 = 2.303/900 log0.85/[A]
log0.85/[A] = 1.9*10^-3*900/2.303
log0.85/[A] = 0.743
0.85/[A] = 10^0.743
0.85/[A] = 5.5335
[A] = 0.85/5.5335 = 0.154M
zero ordr
K = 2.8*10^-4sec
t = 75sec
[A]t = 9*10^-2M = 0.09M
Kt = [A]t - [A]0
2.8*10^-4*75 = 0.09-[A]0
0.021 = 0.09-[A]0
-[A]0 = 0.021-0.09
[A0] = 0.069M