How many moles are there in a 2.0g sample of NaCl?

Strictly, the compound NaCl does not have "moles", because the compound is ionically bonded. The gram formula unit mass, which is substituted for molar mass for ionic compounds, is 58.44, and 2.00 g of NaCl therefore contains 2.00/58.44 or 3.42 X 10-2 gram formula units.