Question

1. A vinegar solution is 4.00% acetic acid by mass. If the solution has a density of 1.04 g/mL, what is the [HC2H2O2) in the solution?

Answer 1

If the mass of the solution is 100 g, then the mass of acetic acid = 4.00 g

Molar mass of acetic acid = 60.1 g/mol

Moles of acetic acid in the solution = mass of acetic acid/molar mass of acetic acid

                                                       = 4.00 g/60.1 g/mol

                                                       = 0.0666 mol

Now, the mass of the solution (m) = 100 g

Density of the solution (d) = 1.04 g/mol

Volume of the solution = m/d

                                    = 100 g/1.04 g/mol

                                    = 96.2 mL

                                    = 0.0962 L                ( $\because$ 1 mL = 0.001 L)

Now,

[HC₂H₃O₂] = moles of acetic acid/liter of solution

                  = 0.0666 mol/0.0962 L

                  = 0.692 M