Question

A particular oral contraceptive contains 0.035 mg of ethinyl estradiol in each pill. The formula of this compound is C2oH402. How many molecules of ethinyl estradiol are there in one pill? (give answer to 3 digits) Submt Anawer Incorrect. Tries 16/99 Previous Tries How many carbon atoms are there in one of these pills (due to the presence of ethinyl estradiol)? (give answer to 3 digits) Submit Answer Incorrect. Tries 1/99 Previous.Tries What mass of carbon is this? (Enter the answer in grams.) Submit Answer Tries 0/99

Answer 1

molar mass of ethynylestradiol = 296.403 g/mol

mole of ethynylestradiol = mass / molar mass = 0.000035 g / 296.403 g/mole = 1.181 * 10^-7 mole.

number of molecules of ethynylestradiol = 1.181 * 10^-7 * 6.023 * 10^23 = 7.11 * 10^16

number of C atoms in one pill = 7.11 * 10^16 * 20 = 1.42 * 10^18

296.403 g ethynylestradiol contains 20 * 12 = 240 g

0.000035 g ethynylestradiol contains = 240 * 0.000035 / 296.403 = 2.83 * 10^-5 g = 0.0283 mg