Osmosis video - Limiting reactants and percent yield

A limiting reactant in a chemical reaction is the reactant that's used up first, so, it's the one that limits the amount of products that are created in a chemical reaction. The other reactants are then said to be in excess. To get the most out of a chemical reaction, it's important to use the correct amounts of all the reactants. If you have too much of one reactant and not enough of another, you won't get the maximum yield.

The percent yield is a measure of how efficient a chemical reaction is. It's calculated by comparing the amount of product that's actually produced to the maximum amount that could be produced under perfect conditions. A percent yield below 100% means there was some loss of product during the reaction. This can happen due to incomplete mixing or because some reactants are used up before others.