rate law

[405773279]

when writing the rate of the reaction, why are products not taken into consideration? in other words, why is the rate always in terms of the reactant

[Ryan Sebti 3I]

We only consider the initial concentrations of reactants when in the rate law, because the rate of a reaction changes (generally decreases) over time, so to normalize rates so reactions can be compared we calculate the initial rate of the reaction, which would occur when the reactants are at their initial concentrations and products are at 0 concentration. This assumption also helps to simplify calculating the rate of reaction, since we no longer need to worry about concentrations of both reactants AND products, instead just reactants.

[Lidia_1I]

Since we only study the initial reaction rates, the product concentration is usually 0 or rather we assume it is. this means the rates depend only on the reactant concentration.

[705995679]

The rate law is always in terms of the reactants because it is the forward reaction. And, the purpose of the rate law is to show the chemical reaction rate in terms of reactant concentration so that's why as previously mentioned, the product concentration is assumed to be 0.

[705801855]

Products are not taken into consideration because we only take into account the forward reaction, and product concentration is taken to be zero. This helps chemists calculate rates of reaction, because changing product concentration can be ignored.

[samaagwani-disc2L]

When writing the rate of the reaction, we only use the reactants and not look at the products because we are looking at the initial reaction rates and are assuming that the product concentration is zero. Another thing that can help you remember this is that the reactant is the forward reaction, so that is why we use reactants and ignore the products. I hope this helps!