Question

approximately how many grams of sodium chloride (NaCl) are required to prepare 500. mL of 3.00 M solution

Answer 1

3.00 M  means 3.00 mol/L. So if you want 500 mL=0.5 L, it needs 3.00 mol/L * 0.5 L = 1.50 mol. For NaCl, the molar mass is 23+35.5=58.5 g/mol. So the amount of NaCl needed is 1.50*58.5=87.75 g. So the answer is 87.75 grams.