What is the mass percent of vitamin C in a solution made by dissolving 5.20 g of vitamin C, C6H8O6, in 55.0 g of water

The correct answer is 8.4 %

Explanation:

The mass percent of a compound in a solution is calculated as follows:

mass percent = mass of solute/mass of solution x 100

The solute is vitamin C, so its mass is:

mass of solute = 5.20 g

The solvent is water, and its mass is 55.0 g. The mass of the solution is given by the sum of solute + solvent:

mass of solution= 5.20 g + 55.0 g = 60.2 g

Finally we calculate the mass percent:

mass percent = 5.20 g/60.2 g x 100 = 8.64%

i believe you are right for all except the 3rd ( look at sqdancefan his answer is much better)