What is the mass of sodium chloride used to create a 100 mL solution at a concentration of 1.5 M? Solution must include a step by step solution with units included throughout, please help?

Answer 1

What is 1.5 M? This means 1.5 molar, which means 1.5 moles of sodium chloride (NaCl) per 1 liter of solution.

Since the question asks to make 100 ml, not 1 liter, we need to make that adjustment.

Molar mass NaCl = 22.99 = 35.45 = 58.44 g/mol

1.5 moles = 1.5 moles x 58.44 g/mol = 87.66 g. This is the mass needed to make 1 liter (1000 ml).

Since we need only 100 ml...

87.66 g/1000 ml x 100 ml = 8.766 g = 8.8 g NaCl needed (to 2 significant figures)

Procedure: weigh out 8.8 g NaCl and place into a 100 ml volumetric flask. Add sufficient d. H2O to make 100 ml of solution.

Answer 2

Molarity (M) = mol/L

100 mL = 0.1 L

1.5 (mol/L) x (0.1L) = 0.15 mol NaCl

Molecular weight of NaCl = 58.44 g/mol

(0.15 mol NaCl ) x (58.44 g/mol NaCl) = 8.77 g NaCl needed for 100 mL of 1.5 M NaCL