Limiting Reactants

[Aren_Kasparian_1G]

When finding a limiting reactant, must I always compare grams of one substance to the grams of another, or can I simply compare the number of moles produced?

[Erika Li 1E]

When finding the limiting reactant, you can either compare the moles of product formed for each reactant or compare the grams of product formed for each reactant. In both cases, the reactant that produces the least amount of product is the limiting reactant. Alternatively, another way to find the limiting reactant is to convert the given mass of each reactant to moles (using molar mass) and compare the mole ratio of the reactants to the mole ratio present in the balanced equation. Hope this helps!

[cecilia1F]

I think for the limiting reactant it's always important to go back to the molar ratio because that will tell you which one is the limiting. It might be that a reactant with a lower amount in grams actually has the correct number of moles to carry out the reaction.

[Tammy Shen 2L]

There are two methods in finding the limiting reactant. You can calculate the number of moles of each reactant and compare the molar ratio between the reactants using the balanced equation. Or, you can compare the grams of each reactant and total product produced to find which reactant yields less product (thus the limiting reactant).

[Jaden Nguyen 2A]

The surest way of knowing which reactant is the limiting reactant is by converting the grams of each of the reactants into moles and assessing the molar ratio of the balanced equation. Take that molar ratio/stoichiometric ratio and determine how much of each reactant is needed to react with the other reactant. If you find that the number of moles of one of the reactants calculated uses more than is provided by the problem then the other reactant is the limiting reagant/reactant.

[indigoaustin 3H]

To find the limiting reactant you can either:
- convert grams of reactants to grams of products using molar mass and stoichiometric coefficients, whichever creates less product is limiting
or
- convert grams of reactants to moles, use stoichiometric coefficients to compare which reactant would run out first

[Matthew Li 1B]

you can use the number of moles to find the limiting reactant.











the one reactant that produces the least amount of moles of the product is the limiting reactant.

[JasmineReyes-2K]

I always like to think of the smallest value being it, either unit !

[Nicole 3G]

I think comparing the number of moles produced for each reactant given should be enough...if it helps you to convert to grams after solving it out that should be okay too as long as you're comparing the amount of product.

[Edwin Montalvo 1G]

These are the two ways:
1) Convert the grams of reactants into moles and compare them to their respective stoichiometric ratios. If, for example, the equation requires 1 mole of reactant A for 5 moles of reactant B, and you end up not having enough reactant B to satisfy that ratio, then reactant B is the limiting reactant.

2) Convert the grams of reactants into moles and determine how much product each reactant would create (in moles, preferably). The reactant that creates the least product is the limiting reactant.

[Chem_Mod]

Hello Aren,

Another method as you noted, which is fine, is to compare which reactant produces the least amount of product (i.e. the "limiting" reactant which "limits" how much product is formed).