Determining slow step

[Carolina Gomez 2G]

How do you know if one of the reactants is not involved in the slow step? How do we determine which of the reactants is the slow step?

[Dylan_K_3B]

Only reactants in the overall rate law are part of the slow step. If a reactant in the chemical equation is not present in the rate law, that means it is part of the fast step. To determine the slow step, it will either be provided that a particular elementary reaction is the slow step, or it can be indicated by the step with the greater activation energy.

[Ashley Lopez 3J]

Reactants are only ever part of the slow step if they are in the overall rate law, which is a determinant of a slow step.

[Riddhi Mehta 2C]

Thus far, we have learned that the reactant in the overall rate law are the reactants in the slow step. Basically looking at the overall reaction tells you what the reactants are for the slow step equation.

[MMorcus2E]

Yeah, I agree with what was said so far. The reactants that are left after canceling out intermediates and end up in the overall equation are the ones that are from the slow step. Also, the reactants in the slow step should match the ones in the rate law.

[Chinmayi Mutyala 3H]

You look at the overall reaction. Anything that isn't in the overall reaction is an intermediate.

[Joshua Chung 2D]

If the reactants of the slow step are not given, just keep in mind that they will always be a part of the rate law.

[Alexandra Ahlschlager 1L]

Intermediates which are produced first and then consumed will not be included in the rate law even if they are in the slow step. To answer your second question, the slow step will have the highest activation energy and its reactants will be in the final rate law. Hope this helps!

[Stephanie Zhang 2K]

yes, you usually look at the overall rate law and see which reactants are part of it, and then match that to the elementary step which also has the same reactants. Or, the problem would give you the slow step. Only the reactants in the slow step are included in the rate law. If you see a reactant in the slow step rate law that isn't part of the overall reaction reactant, that usually indicates that the reactant may be an intermediate, in which case you'd have to use the pseudo-rate law (solve for the concentration of that reactant using the fast equilibrium step before the slow step and plug that in to the slow step rate law).

[Shruti Kulkarni 2I]

You can tell if a reactant is part of the slow step if it is present in the overall rate law, as that only includes the reactants in the slow step.

[David Liu 1E]

The slow step should have the highest activation energy, and you would also find the products of the slow step in the final reaction!

[Jacob Schwarz-Discussion 3I]

I usually can tell by knowing that the reactants in the slow step are part of the overall rate law.

[David Jen 1J]

Many questions will straight up tell you which step is the slow step, but in case it doesn't, the slow step tends to make up the overall rate law.

[JoshMoore2B]

How do you know if one of the reactants is not involved in the slow step? How do we determine which of the reactants is the slow step?

I think it is safe to assume that the slowest step will be outlined for us.

If not, then you can find the rate laws for each step and compare it to the overall. Since the slow step is the rate determining step, it will match the overall rate law.

[Jack_Pearce_2H]

Usually they will tell you which one is the slow step. If it is not given in the problem, the step whose rate law which resembles the primary rate law is the slow step. You can identify intermediates because they do not appear in the primary rate law.

[Gicelle Rubin 1E]

yes, you usually look at the overall rate law and see which reactants are part of it, and then match that to the elementary step which also has the same reactants. Or, the problem would give you the slow step. Only the reactants in the slow step are included in the rate law. If you see a reactant in the slow step rate law that isn't part of the overall reaction reactant, that usually indicates that the reactant may be an intermediate, in which case you'd have to use the pseudo-rate law (solve for the concentration of that reactant using the fast equilibrium step before the slow step and plug that in to the slow step rate law).

thank you! i think i finally understand :)

[Diana Aguilar 3H]

The way you know if one of the reactants is part of the slow step is if they are part of the overall rate law, but usually the question will tell you.

[Shana Patel 1C]

The slow step should have the highest activation energy.
You would also find the products of the slow step in the final reaction.

[Moura Girgis 1F]

It is only when they are in the overall rate law that the reactants are involved in the slow step.

[Taha 2D]

the reactants shown to be in the rate law are the ones which are involved in the slow step

[Jacob_Eberson_2D]

the reactants in the rate law are those in the slow step

[Saatvika Nair]

Reactants will be in the slow step if they are part of the overall rate law, otherwise they won't be. You can tell if a reactant won't be in the slow step, because no intermediates are in the overall rate law. Then that means that they must be in the fast step.

[Zoe Dhalla 3I]

The overall reaction rate depends almost entirely on the rate of the slowest step. If the first step is the slowest, and the entire reaction must wait for it, then it is the rate-determining step. he slowest step of a chemical reaction can be determined by setting up a reaction mechanisms. Many reactions do not occur in a single reaction but they happen in multiple elementary steps. But usually, reactants that are shown in the rate law are the ones that are involved in the slow step.