Water in Rate Law Equation

[Rayna Irving 2C]

Quick question, do we ever include water when writing a rate law equation?

[Brennan McGurrr 3C]

In an aqueous solution, the concentration of water cannot be measured. It will not have an effect on the rate of the reaction, so it is not included in the rate law.

[Izamary Marquez 2H]

It doesn't have a specific effect, so we typically don't include it.

[Valerie Tran 2B]

It can be included if it is present in the reaction mechanism but we usually leave it out because its concentration doesn't affect the rate.

[Christine Ma 3L]

Most of the time we don't include water in our rate laws because it is usually the solvent and thus any change in its concentration is negligible. However, when water is not the solvent, we do have to include it in the rate law.

[RyanKopeikin_2I]

Water would only be included in the rate law equation if it was part of the rate-determining (slowest) step, and an organic solvent is being used (So water is not the solvent). As long as water IS the solvent, it won't be included in the rate law.

[Kiana Tashakori 1D]

No, you don't have to include water because its concentration doesn't affect the rate.

[Alan Nguyen 2I]

Liquid water does not have a concentration, meaning that it does not affect the rate law. Remember, the definition of a rate law states that it shows how fast a reaction proceeds based on reactant concentration. Because water does not make sense to have a concentration, it is not included in the rate law.

[Grant_2A]

usually not because it doesn't affect the rate in most cases.

[Emily Quill 2H]

Since it's concentration typically does not affect the rate it is usually not included.

[David Facio 3C]

This is similar to when something is in excess. We don't take that excess water into account because it is considered an aqueous solution, therefore it will not have a large enough effect.

[Amanda Dankberg 1B]

We do not include water when it is the solvent (which is most of the time) but do include it when it is not (when it is a gas)

[Bela Patel 2B]

Including water in a rate law equation has no effect on the rate of the reaction and the concentration of water can not be measured in an aqueous solution, so therefore we do not include water in rate law equations.

[Aaron Martinez]

Like with equilibrium concentration formulas, we don't include water. This is because it is a pure liquid, and hard to measure the concentration of. It also doesn't really affect the speed of a reaction.

[Amy Jordan 2A]

Hi, when water is in its aqueous form we don't include it because its concentration isn't measured so it doesn't affect the rate of the reaction.