# Involving Rate determining steps

• Foon
In summary, the conversation discusses a proposed mechanism for a general reaction and the determination of the rate law equation. The first step of the mechanism involves the formation of a intermediate, C, which is then consumed in the second step of the reaction. The final equation shows that the rate law equation is consistent with the proposed mechanism.

#### Foon

I have no idea how to figure this one out, I've been hacking away at it all evening. Please help

Consider the general reaction:

2A + B --> 2E + F

The experimentally determined rate law equation is written as follows:

Rate = k[A]

A proposed mechanism for the reaction has the first step below:

Step 1: A + B --> C + F (rate determinging step)

Assuming a two-step mechanism, write a possible second elementary reaction for this mechanism.

And this is what I have but I'm not sure if its right. And I'm totally puzzled as to how they get rid of the C.

Step1: A + B --> C + F
Step2: A --> C- + 2E
------------------------
2A + B --> 2E + F

It has to be totally wrong since they've given me a rate law which I have no idea how to use.

HW, so this is going to be a step at a time: 1) what's the ORDER of the reaction --- you've got a rate expression; 2) what else does the rate expression tell you; 3) WHAT is "C"?

You're almost there. For the second equation put C on the left side. That should do it.

Do what meninger said. C is the intermediate in the reaction, therefore it can't be in the final product at all.

## What is a rate determining step?

A rate determining step is the slowest step in a chemical reaction, which ultimately determines the overall rate of the reaction. It is also known as the rate-limiting step.

## How do you identify the rate determining step?

The rate determining step can be identified by analyzing the reaction mechanism and determining which step has the highest activation energy. The step with the highest activation energy is typically the slowest step and therefore the rate determining step.

## Why is it important to understand the rate determining step?

Understanding the rate determining step is important because it allows us to predict and control the rate of a chemical reaction. By identifying the slowest step, we can focus on optimizing the conditions of that step to increase the overall reaction rate.

## Can the rate determining step be changed?

Yes, the rate determining step can be changed by altering the reaction conditions, such as temperature, pressure, or concentration of reactants. This can lead to a change in the overall reaction rate.

## Why do some reactions have multiple rate determining steps?

Some reactions may have multiple rate determining steps if they involve complex reaction mechanisms with multiple intermediate steps. In these cases, each intermediate step may have a different activation energy, resulting in multiple rate determining steps.