作业帮AP chemistry的一道题目
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AP chemistry的一道题目
Step 1:N2H2O2 N2HO2- + H+ (fast equilibrium)
Step 2:N2HO2- N2O + OH- (slow)
Step 3:H+ + OH- H2O (fast)
Nitramide,N2H2O2,decomposes slowly in aqueous solution.This decomposition is believed to occur according to the reaction mechanism above.The rate law for the decomposition of nitramide that is consistent with this mechanism is given by which of the following?
(A) Rate= k[N2H2O2]
(B) Rate= k[N2H2O2][H+]
(C) Rate= k[N2H2O2]/[H+]
(D) Rate= k[N2H2O2]/[N2HO2-]
(E) Rate= k[N2H2O2][OH-]
Answer:C
请具体讲一讲为什么选C啊?
Step 1:N2H2O2 N2HO2- + H+ (fast equilibrium)
Step 2:N2HO2- N2O + OH- (slow)
Step 3:H+ + OH- H2O (fast)
Nitramide,N2H2O2,decomposes slowly in aqueous solution.This decomposition is believed to occur according to the reaction mechanism above.The rate law for the decomposition of nitramide that is consistent with this mechanism is given by which of the following?
(A) Rate= k[N2H2O2]
(B) Rate= k[N2H2O2][H+]
(C) Rate= k[N2H2O2]/[H+]
(D) Rate= k[N2H2O2]/[N2HO2-]
(E) Rate= k[N2H2O2][OH-]
Answer:C
请具体讲一讲为什么选C啊?
The rate law is determined in this case by the slowest reaction step:
rate = k[N2HO2-]
Equilibrium for step before the slowest step:
K = [N2HO2-][H+] / [N2H2O2]
K[N2H2O2] / [H+] = [N2HO2-]
rate = k{K[N2H2O2] / [H+]}
rate = (k1)[N2H2O2] / [H+]
rate = k[N2HO2-]
Equilibrium for step before the slowest step:
K = [N2HO2-][H+] / [N2H2O2]
K[N2H2O2] / [H+] = [N2HO2-]
rate = k{K[N2H2O2] / [H+]}
rate = (k1)[N2H2O2] / [H+]