To find the number of atoms in any quantity of moles you just need to multiply the number of ,moles times Avogadro's constant, which will gives the number of molecules, and then multiply by the number of atoms is one molecule which is 5 (C, H, and 3 Cl). The calculus is 1.75 mol 6.02 10^23 molecules/mol 5 atoms/molecule= 52.675 10^23 atoms = 5.2675 * 10^ 24 atoms.
