What is the mass, in grams, of 7.20*1020 molecules of caffeine, c8h10n4o2?

To determine the mass, you need to know the molecular weight of the c8h10n4o2. The molecular weight of c8h10n4o2 would be: 8*12 + 10*1 + 4*14 + 2*16 = 194g/mol.

To convert the number of molecules into moles, you need to divide it with 6.02 * 10^23. The calculation of the mass of c8h10n4o2 would be:

(7.20*10^20 molecules) / (6.02 * 10^23 molecule/mol) * 194g/mol = 232 * 10^-3 grams = 0.232 grams