To find the number of molecules, we'll use Avogadro's number (6.022 x 10^23 molecules/mol).Given: 3.4 mol NaClNumber of molecules = moles x Avogadro's number= 3.4 mol x 6.022 x 10^23 molecules/mol≈ 2.04748 x 10^24 moleculesSo, there are approximately 2.05 x 10^24 NaCl molecules.