What mass of air is necessary for the formation of 63 g of ammonia, if nitrogen in the air is 77% by mass?

Getting ammonia from nitrogen is possible by hydrogenation of the latter. This reaction takes place in the presence of a catalyst at high temperature and pressure. Obtaining ammonia in this way is named the Haber process – in honor of the scientist who first carried it out.

The equation for this reaction looks like this:

N2 + 3 H2 = 2 NH3

Let us calculate by this equation the mass of nitrogen required to obtain 63 g of ammonia, and then calculate the mass of air.

Molar mass of nitrogen = 28 g / mol; molar mass of ammonia = 17 g / mol

Let’s make the proportion:

X g of nitrogen corresponds to 63 g of ammonia, as

28 g / mol nitrogen corresponds to 2 * 17 g / mol ammonia

X = (63 * 28) / (2 * 17) = 51.88 g of nitrogen.

51.88 g of nitrogen is 77% of the mass of air, which means the mass of air = (51.88 * 100) / 77 = 67.38 g.

Answer: air mass 67.88 g.