Molarity is only one of many ways to express concentration. Another is percent mass per volume or %(m/v). For example, vinegar usually contains about 5 %(m/v) acetic acid(5g acetic acid/100 mL vinegar). Calculate the molarity of acetic acid in a vinegar that is 5.5%(m/v)acetic acid. The molecular formula of acetic acid is C2H4O2.