Question

How many moles of nitrogen are needed to completely react with two moles of hydrogen?

N2+3h2>2NH3

Answer 1

`2/3` `"mol N"_2"` is required to react completely with `"2 mol H"_2"` in the given equation.

Explanation:

Balanced equation

`"N"_2("g") + "3H"_2("g")"` `rarr` `"2NH"_3"`

Mole ratios from the balanced equation

`("1 mol N"_2)/("3 mol H"_2")` and `("3 mol H"_2)/("1 mol N"_2")`

Moles nitrogen gas needed to react with 2 mole hydrogen gas.

Multiply `"2 mol H"_2` by the mole ratio that has `"N"_2` in the numerator, which will cancel `"mol H"_2` in the denominator.

`2color(red)cancel(color(black)("mol H"_2))xx("1 mol N"_2)/(3color(red)cancel(color(black)("mol H"_2)))` `=` `"2"/"3"` `"mol N"_2"`