What is the molarity of a solution which contains 58.5 g of sodium chloride dissolved in 0.500 l of solution?

The units of molarity are moles/liter, so you want to find the number of moles in one liter of a substance.

The molar mass of Sodium Chloride (NaCl) is approximately 58.5, gotten from the sum of the molar masses of sodium and chlorine

Molar Mass sodium = 23.0 grams/mole

Molar Mass chlorine = 35.5 grams/mole

Molar mass sodium chloride = 23.0 g/mol + 35.5 g/mol = 58.5 g/mol

Convert 58.5 grams to moles: (58.5 grams) / (58.5 grams/mol)

Leaves 1.00 moles of NaCl

Divide that by the number of liters of solution (0.500 liters)

(1.00moles) / (0.500 liters) = 2.00 moles/liter is your molarity