What is the mass of
6.02 x 10^23 molecules of vitamin A
(C20H30O)?
[?] g C20 H 30 O

Answer: 286.44 grams of vitamin A
Explanation:
Here, just use the atomic masses of C (12.01 g/mol), H(1.008 g/mol), and O (16 g/mol), multiply each by their respective subscripts, add them together, and divide them by Avogadro's number, which is 6.02*10^23. Since this is exactly 1 mol of vitamin A, we neglect the division since they end up cancelling out. If we do the math, multiplying mass by subscript and adding,
(12.01)(20) + (1.008)(30) + (16)(1) = 286.44 g/mol, and since we have exactly one mole of vitamin A, we have 286.44 grams of vitamin A
Correct me if I am wrong, but I think you are using Acellus, which I think is really cool since that's what I used for middle and high school.