Question

How many moles of ammonia are produced from the reaction of four moles of hydrogen?

`"N"_2 + "3H"_2"` `rarr` `"2NH"_3"`

Answer 1

`2 2/3` mole `"NH"_3` can be produced from `"4 mol H"_2"`.

Explanation:

Balanced Equation

`"N"_2+"3H"_2"` `rarr` `"2NH"_3"`

The mole ratio between `"H"_2"` and `"NH"_3"` in the balanced eqution is:

`("3 mol H"_2)/("2 mol NH"_3)` or `("2 mol NH"_3)/("3 mol H"_2)`.

Multiply the given mol `"H"_2"` by the mol ratio between `"H"_2` and `"NH"_3` from the balanced equation, with `"NH"_3` in the numerator so that `"H"_2` cancels, leaving `"NH"_3`.

`4color(red)cancel(color(black)("mol H"_2))xx(2"mol NH"_3)/(3color(red)cancel(color(black)("mol H"_2)))` `=` `8/3 "mol NH"_3"` `=` `2 2/3 "mol NH"_3"`