An alka-seltzer tablet contains 324 mg of aspirin (c9h8o4), 1904 mg of nahco3 and, 1000. mg of citric acid (h3c6h5o7). (the last two compounds react with each other to provide the "fizz," bubbles of co2, when the tablet is put into water.) if you take three tablets, how many molecules of aspirin are you consuming?

Each alka-seltzer tablet contains 324 mg of aspirin. Three alka-seltzer tablet contains (3 x 324)mg= 972 mg of aspirin= 0.972 g of aspirin.

Molecular formula of aspirin is C₉H₈O₄. Molar mass of aspirin is (9 x 12)+(8 x 1)+(4 x 16) g/ mol= 180 g/mol.

180 g of aspirin contains 1 mole of aspirin molecules i.e, 6.023 X 10²³ number of aspirin molecules.  So, three alka-seltzer tablet that is 0.972 g of aspirin contains (0.972 X 6.023 X 10²³)/180 =3.25 X 10²¹ number of aspirin molecules.