Question

To reduce dangerous swelling in the brain, physician sometimes administer intravenous hypertonic saline, a 5.0%(w/v) Solution of salt (NaCI) In water. Calculate the volume of the solution that contains 0.50 g of NaCl. Be sure your answer has unit symbol and his rounded to the correct number of significant digits

Answer 1

Percent weight/volume (% w/v) is a way of expressing the concentration of a solutuon. The definition of it is:

% w/v = mass of solute /100 ml of solution

We have to find the volume of the 5.0 % (w/v) solution that contains 0.50 g of NaCl. So we are given these values:

Concentration % w/v = 5.0 %

mass of solute = 0.50 g

Since our solution is 5.0 % w/v Nacl, we know that it has 5.0 g NaCl in 100 ml of solution. So if we want to find the volume of solution that contains 0.50 g we can:

0.50 g of NaCl * 100 ml of solution/(5.0 g of NaCl) = 10. ml of solution.

10. mL of solution is the volume that contains 0.50 g of NaCl