Question

What mass of carbon monoxide is required to react completely with 318g of iron(III) oxide?

Answer 1

The balanced equation for this reaction is $3\text{CO}+\text{Fe}_{2}\text{O}_{3} \longrightarrow 2\text{Fe}+3\text{CO}_{2}$.

This means that for every mole of iron(III) oxide consumed, 3 moles of carbon monoxide are consumed.

• Iron has an atomic mass of 55.845 g/mol.
• Oxygen has an atomic mass of 15.999 g/mol.

This means that iron(III) oxide has a formula mass of 2(55.845)+3(15.999)=g/mol, and thus 318 g is equal to $\frac{318}{159.687}=1.9913956677751 \text{ mol}$.

So, this means we need $3(1.9913956677751)=5.9741870033253 \text{ mol}$ of CO.

• Carbon has an atomic mass of 12.011 g/mol.
• Oxygen has an atomic mass of 15.999 g/mol.

This means CO has a formula mass of 12.011+15.999=28.01 g/mol, and thus 5.9741870033253 moles have a mass of (28.01)(5.9741870033253), which is equal to about 167 g (to 3 sf)