Question

One cup of fresh orange juice contains 139 mg of ascorbic acid (vitamin c, c6h8o6) given that one cup = 264.8 ml calculate the molarity of vitamin c in organic juice.

Answer 1

The answer to this question would be: 3 molar
A molar unit will be equal to moles of solute per 1 liter of solvent. In this question, you are given the volume of the solution (264.8ml) and the weight of the molecule(139mg). Since the unit is moles not mg, then you need to convert the molecule into moles. To do that you need to know the ascorbic acid molecular weight which was: 6*12 + 8*1 + 6 *16 =176mg/moles.

molecule in moles= 139mg/ (176 mg/moles)= 0.79 moles

Then the molarity of the juice should be: 0.79 moles/ (1000ml/264ml)= 2.991 M= 3 M