Question 51 in the homework [ENDORSED]

$\frac{d[R]}{dt}=-k[R]^{2}; \frac{1}{[R]}=kt + \frac{1}{[R]_{0}}; t_{\frac{1}{2}}=\frac{1}{k[R]_{0}}$

104422816
Posts: 17
Joined: Fri Sep 25, 2015 3:00 am

Question 51 in the homework

15.51 The following mechanism has been proposed for the reaction between nitric oxide and bromine:
Step 1: NO -> Br2 + NOBr2 (slow)
Step 2: NOBr2 + NO + NOBr -> NOBr (fast)
Write the rate law for the formation of NOBr implied by this mechanism.

The explanation for the answer: k(NO)(Br2) says that this is a second order reaction but i thought second order equation is (a)^2

Reine Nakamura 1C
Posts: 38
Joined: Fri Sep 25, 2015 3:00 am

Re: Question 51 in the homework

It's a second order reaction because the overall order of the reaction is the sum of the orders for [NO] and [Br2]. In this case both are first order, making the overall order 2.

Posts: 59
Joined: Fri Sep 29, 2017 7:07 am

Re: Question 51 in the homework  [ENDORSED]

Why is the speed of the rxn relevant in this problem? (slow vs fast)

Chem_Mod
Posts: 17238
Joined: Thu Aug 04, 2011 1:53 pm
Has upvoted: 367 times

Re: Question 51 in the homework

This is to show that the first step is the most important overall for determining reaction rate, as it is slower than the second, making it rate-limiting.

Dang Lam
Posts: 55
Joined: Thu Jul 27, 2017 3:01 am

Re: Question 51 in the homework

Chem_Mod wrote:This is to show that the first step is the most important overall for determining reaction rate, as it is slower than the second, making it rate-limiting.

so which reaction (slow or fast) should we use to write our rate law?

Who is online

Users browsing this forum: No registered users and 1 guest