Question

How many grams of nitrogen are necessary to produce 15.00 grams of ammonia?

Answer 1

The required mass of nitrogen is 12.34 g.

Explanation:

The balanced equation is:

`0.5"N"_2 + 1.5"H"_2 rarr "NH"_3 color(white)(..................................)(1)`

The molecular mass of ammonia, `"NH"_3`, is equal to 14.01 g + 3(1.008 g), or 17.03 g.

`"Moles of ammonia" = "mass in grams"/"molecular mass" ="15.00 g"/"17.03 g/mol" = 15.00/17.03 " mol"`

Therefore, according to equation `(1)`,

`"Moles of nitrogen" = 0.5(15.00/17.03) " mol" color(white)(............) (2)`

The number of moles of nitrogen is calculated by the following equation:

`"Moles of N"_2 = ("mass of nitrogen")/ ("molar mass of nitrogen")`

Thus,

`"Mass of nitrogen" = "moles of N"_2*"molar mass of N"_2 color(white)(...) (3)`

Therefore, from equations `(2)` and `(3)`, we have:

`"Mass of nitrogen" = 0.5(15.00/17.03) " mol" xx "28.02 g/mol" = "12.34 g"`

With kind regards
Dr. Mamdouh Younes
Hamilton, Ontario, Canada