Problem: Which sample contains the greatest number of moles of Cl?(a) 3.8 mol HCl(b) 1.7 mol CH2Cl2(c) 4.2 mol NaClO3(d) 2.2 mol Mg(ClO4)2

(a) 3.8 mol HCl

1 mol HCl: 1 mol Cl

$\mathbf{moles}\mathbf{ }\mathbf{Cl}\mathbf{ }\mathbf{=}\mathbf{3}\mathbf{.}\mathbf{8}\mathbf{ }\cancel{\mathbf{mol}\mathbf{ }\mathbf{HCl}}\mathbf{\times }\mathbf{\times }\frac{\mathbf{1}\mathbf{ }\mathbf{mol}\mathbf{ }\mathbf{Cl}}{\mathbf{1}\mathbf{ }\cancel{\mathbf{mol}\mathbf{ }\mathbf{HCl}}}$

moles Cl = 3.8 mol

(b) 1.7 mol CH₂Cl₂

1 mol CH₂Cl₂: 2 mol Cl

$\mathbf{moles}\mathbf{ }\mathbf{Cl}\mathbf{ }\mathbf{=}\mathbf{1}\mathbf{.}\mathbf{7}\mathbf{ }\cancel{\mathbf{mol}\mathbf{ }{\mathbf{CH}}_{\mathbf{2}}{\mathbf{Cl}}_{\mathbf{2}}}\mathbf{\times }\mathbf{\times }\frac{\mathbf{2}\mathbf{ }\mathbf{mol}\mathbf{ }\mathbf{Cl}}{\mathbf{1}\mathbf{ }\cancel{\mathbf{mol}\mathbf{ }{\mathbf{CH}}_{\mathbf{2}}{\mathbf{Cl}}_{\mathbf{2}}}}$

moles Cl = 3.4 mol

(c) 4.2 mol NaClO₃