Overall Order

[Alyssa Cheung-2J]

When we calculate the overall order of an equation, we add together the individual powers but I was wondering why that is? How does it make sense conceptually to add together the individual orders to get one overall vs say multiplying them

[MarissaSmith1B]

Hi! How I think of it is that the order of each reactant describes how much the individual substances react, whereas the overall reaction order shows the total change in the reactants. This lets us see how the change in each of the reactants affects the overall rate, as the overall order is the sum of the orders of each reactant.

[106033555]

because when you multiply concentrations, you add up the exponents. it follows the product law: a^m * a^n= a^m+n

[Maegan Abutin 2C]

Hi.

We add together the individual powers instead of multiplying because it reflects the contributions of each reactant to the rate of the reaction based on their reaction mechanisms. If we were to multiply the orders, it would be a totally different relationship that doesn't reflect behavior in simple chemical reactions. Also, in the Rate Law, m and n are the orders of the reaction with respect to A and B. The overall order is solved by using m+n.