# How can you find a limiting reactant using moles?

Feb 8, 2017

For this you just have to watch the balanced equation of the reaction.

#### Explanation:

For eg:

${\text{N"_2 + 3"H"_2 -> 2"NH}}_{3}$

This means that $1$ mole of ${\text{N}}_{2}$ reacts with $3$ moles of ${\text{H}}_{2}$ and makes $2$ moles of ${\text{NH}}_{3}$.

If you are given $5$ moles of ${\text{N}}_{2}$ and $9$ moles of ${\text{H}}_{2}$, then what's the limiting reagent?

You can find it here

${\text{1 mole N}}_{2}$ ${\text{reacts with 3 moles H}}_{2}$

${\text{2 moles N}}_{2}$ ${\text{react with 6 moles H}}_{2}$

${\text{3 moles N}}_{2}$ ${\text{react with 9 moles H}}_{2}$

Oh see!! The ${\text{H}}_{2}$ moles are consumed when $3$ moles of ${\text{N}}_{2}$ react. But you have $5$ moles of ${\text{N}}_{2}$ available, so in this case, ${\text{H}}_{2}$ is the limiting reagent.

Hope you understand.