Possession of Cocaine

by The National Archives UK

Question by dbdwnd: Find the total number of atoms in a sample of cocaine hydrochloride?
Find the total number of atoms in a sample of cocaine hydrochloride, C17H22ClNO4, of mass 24.5mg.

Best answer:

Answer by MadScientist
The molecular weight is 17*12 +22*1 +35.5 +14 +16*4 = 339.5 g/mol.
The number of moles is 24.5 mg / 339.5 g/mol = 7.216 *10^-5 mol.
There are 35 atoms in each molecule of cocaine HCl, and there are 6.023 * 10^23 molecules / mol, so the number of atoms is:
7.216 E-5 mol * 6.023 E23 molecules / mol * 35 atoms / molecule = 1.521 E21 atoms (or 1.521 sextillion (US), 1.521 trilliard (UK) atoms or 1.521 zeptoatoms (SI))

Comments are closed.