Question

How many grams of H2O will be formed when 17.6 g H2 is mixed with 22.3 g of O2 and allowed to react to form water?

Answer 1

First, write out the balanced reaction:

2 H₂ + O₂ 2H₂O

Find out limiting reagent.

No. of moles = Mass given / Molecular mass

No. of moles of H2 = 17.6 / 2 = 8.8 moles

No. of moles of O2 = 22.3/ 32 = 0.69 moles

From the balanced chemical equation, we can we ratio H2:O2 is 2:1.

Therfore 8.8 moles of H₂ will require 4.4 moles of O₂. Therefore we can say H₂ is present in excess and O₂ is the limiting reagent.

From the chemical equation, we can see 1 O₂ molecule, giving 2 water molecules.

Therefore, 0.69 moles of O₂ will give 1.38 moles of H₂O

Mass of H₂O produced = No. of moles x molecular mass = 1.38 x 18 = 24.84g