Question

What mass of sodium chloride contains 4.59 x 10 24 formula units?

Answer 1

The term formula units means molecules.

Then, what you are looking for is the mass in 4.59*10^24  molecules.

The procedure involves to convert the 4.59 * 10^24 molecules into moles and use the molar mass of the sodium chloride.

1) Number of moles = 4.59 * 10^24 molecules / (6.02 * 10^23 molecules/mol) = 7.62 mol

2) Molar mass of NaCl = 22.99 g/mol + 35.45 g/mol = 58.44 g/mol

3) mass of NaCl = molar mass *  number of moles = 58.44 g/mol * 7.62 mol = 445.31 g of NaCl

Answer: 445.31 g of NaCl.