Which contains the greatest mass of oxygen: 0.75 mol of ethanol (C₂H₅OH), 0.60 mol of formic acid (HCO₂H), or 1.0 mol of water (H₂O)? Explain why.

It is known that 1 mole of ethanol has 1 mole of oxygen atom; therefore, 0.75 mol of ethanol will have 0.75 mol of oxygen.

The molecular mass of oxygen is 16 g/mol. Thus, from the relation between moles, mass, and molecular mass, we can determine the mass of oxygen in ethanol that is

\({\rm{Mass = Moles }} \times {\rm{ Molecular mass}}\)

\({\rm{Mass = 0}}{\rm{.75 }} \times {\rm{ 16 = 12g}}\)

It is known that 1 mole of formic acid has 2 moles of oxygen atom; therefore, 0.60 mol of formic acid will have \(0.60\; \times {\rm{ 2 = 1}}{\rm{.2 mole}}\) of oxygen.

The molecular mass of oxygen is 16 g/mol. Thus, from the relation between moles, mass, and molecular mass, we can determine the mass of oxygen in formic acid that is

\({\rm{Mass = Moles }} \times {\rm{ Molecular mass}}\)

\({\rm{Mass = 1}}{\rm{.2 }} \times {\rm{ 16 = 19}}{\rm{.2g}}\)

It is known that 1 mole of water has 1 mole of oxygen atom; therefore, 1 mol of water will have 1 mol of oxygen.

The molecular mass of oxygen is 16 g/mol. Thus, from the relation between moles, mass, and molecular mass, we can determine the mass of oxygen in water, that is:

\({\rm{Mass = Moles }} \times {\rm{ Molecular mass}}\)

\({\rm{Mass = 1 }} \times {\rm{ 16 = 16g}}\)