A 650 mL sodium bromine solution has a bromide ion concentration of 0.245 M. What is the mass (g) of sodium bromide in solution?

A) 103.

B) 0.00155.

C) 16400.

D) 16.4.

E) 0.159

The correct answer is D: 16.4 g

Explanation:

Look at the balanced equation of NaBr, It has 1:1 between Na and Br.

NaBr - --> Na + and Br-

If the solution has 0.245 concentration of bromide ions then the solution has 0.245 concentration of sodium ions as well. Which means both have equal concentration. So the molarity of solution is 0.245 M.

Convert volume in dm3.

650ml = 650 cm3

650cm3 / 1000cm3 x 1dm3 = 0.65 dm3

Mass of a solute (g) = Molarity x Molar mass of solute x volume in dm3

= 0.245 M X 102.89 g/mol x 0.65 dm3

= 16.38 = 16.4 g