Question

Vitamin C contains the elements C, H, and O. It is known to contain 40.9% C and 4.58% H by mass. The molar mass of vitamin C has been found to be about 180 g/mol. The molecular formula for vitamin C is _________

Answer 1

Answer:

C₆H₈O₆

Explanation:

First off, the percent of oxygen by mass of vitamin C is:

• 100 - (40.9+4.58) = 54.52 %

Assume we have one mol of vitamin C. Then we would have 180 grams, of which:

• 180 * 40.9/100 = 73.62 grams are of Carbon

• 180 * 4.58/100 = 8.224 grams are of Hydrogen

• 180 * 54.52/100 = 98.136 grams are of Oxygen

Now we convert each of those masses to moles, using the elements' respective atomic mass:

• C ⇒ 73.62 g ÷ 12 g/mol = 6.135 mol C ≅ 6 mol C

• H ⇒ 8.224 g ÷ 1 g/mol = 8.224 mol H ≅ 8 mol H

• O ⇒ 98.136 g ÷ 16 g/mol = 6.134 mol O ≅ 6 mol O

So the molecular formula for vitamin C is C₆H₈O₆