Question

2H2 + O2- 2H20

Which conversion factors will you need to calculate the
mass of H2O that is made when 8 grams of H2 react?

Answer 1

Conversion factor : molar mass/molecular weight

Mass of H₂O produced = 72 g

Further explanation

Given

Reaction

2H2 + O2- 2H20

8 grams of H2

Required

Conversion factors

Solution

We can use the molar mass of the components and the mole ratio as conversion factors for the above equation

mol H₂ (MW = 2 g/mol) :

`\tt mol=(8)/(2)=4~mol`

From the equation, mol ratio of H₂ : H₂O = 2 : 2, so mol H₂O = 4 mol

mass H₂O(MW = 18 g/mol) :

mass = mol x MW

mass = 4 x 18

mass = 72 g