How many moles (of molecules or formula units) are in each sample? part a 71.66 g cf2cl2?

Answer is: there is 0,592 moles of CF₂Cl₂.
m(CF₂Cl₂) = 71,66 g.
n(CF₂Cl₂) = m(CF₂Cl₂) ÷ M(CF₂Cl₂).
n(CF₂Cl₂) = 71,66 g ÷ 120,91 g/mol.
n(CF₂Cl₂) = 0,592 mol.
M - molar mass substance.
m - mass of substance.
n - amount of substance.