An Introduction to Limiting Reagents

What is a Limiting Reagent?
A limiting reagent is the substance in an equation that runs out first. Speaking in terms of chemistry, it is the compound that restricts the amount of the new compound that can be made. A real life example would be if you are making lemonade, and the recipe calls for 2 cups of water, and 2 lemons, and you have 8 cups of water and 6 lemons. The lemons would be the limiting reagent because they would run out first, and they decide how much lemonade can be made. 

Why do we use Limiting Reagents? 
We use limiting reagents to tell us how much of a mixture can be created. By knowing which substance we have less of to react with another, we can know how much of a surplus we have, or how much more we may need.