Question

Calculate the molarity, mole fraction, and percent mass formula for a mixture of NaCl (MW=58.44 amu and density = 2.16 g/ml). 15.0g of NaCl are added to 150 mL of H2O (density = 1.00 g/ml)

Answer 1

15.0 g of NaCl are added to 150 mL of H2O

The number of moles of NaCl  

For water, density = 1.00 g/ml. Hence 150 mL water = 150 g

Total mass of solution =

The density of solution 2.16 g/ml

The volume of solution

Molarity is the ratio of the number of moles of NaCl to the volume of solution (in L).

Molarity

Molar mass of water is 18 g/mol. The mass of water is 150 g. The number of moles of water is the ratio of mass of water to molar mass. It is

The mole fraction of NaCl

Formula mass percent