How to Calculate the Molarity of a Vinegar Sample
- 1). Look at the container of vinegar you bought from the store; it should list a pentent concentration or percent acidity somewhere on the bottle. This number is the number of grams of acetic acid per 0.1 liters of vinegar solution.
- 2). Divide this number by 60.05 grams per mole, which is the molar mass of acetic acid. If the vinegar is 5 percent, for example, 5 / 60.05 = 0.083 moles per 0.1 liters of vinegar. You're not quite done yet, however. This answer gives moles per 0.1 liter, whereas you want moles per liter.
- 3). Multiply the answer from the last step by 10. This gives you the molarity or moles per liter. If the vinegar is 5 percent, then, it has 0.83 moles of acetic acid per liter of vinegar.
Source...