W/V Solutions in Grams

Question

How many grams of salt would you add to make a 3% w/v solution with a total volume of 20 ml?

Answer 1

Hello! W/V means weight/volume. Since your volume is 20 mL, the amount of weight we are going to be calculating is the weight in grams.

3% is equivalent to 0.03. The calculation to set this up, therefore, is 0.03=x/20 mL where x is your weight in grams.

Solving this problem, we find that x=0.6 g

Therefore, 3% w/v of a 20 mL solution is 0.6 g.