Question

Ammonia chemically reacts with oxygen gas to produce nitric oxide and water . What mass of ammonia is consumed by the reaction of 4.5g of oxygen gas?

Answer 1

The chemical equation represents the reaction describes is;
4NH3 + 5O2 = 4NO + 6H2O

Therefore 4 moles of NH3 reacts with 5 moles of O2.
1 mole of O2 (molar mass) = 2 * 16 = 32g.
5 moles of O2 = 5 * 32 = 160g
4 moles of NH3 = 4 (14 + 3*1) = 68g

Therefore, 68g of NH3 reacts with 160g of O2.
But, we have only 4.5 g of oxygen.
68g reacts with 160g
Xg reacts with 4.5
X = 68*4.5 / 160 = 1.9125g