Question

How many liters of water must be added to 5.40 g of sodium nitrate to create a solution that has a concentration of 3.81 g/l? use . 0.706 l 1.42 l 1.59 l 20.6 l?

Answer 1

Answer: The volume of water added must be, 1.42 L

Explanation : Given,

Mass of sodium nitrate = 5.40 g

Concentration of solution = 3.81 g/L

3.81 g/L concentration means that, 3.81 grams of sodium nitrate present in 1 liter of water.

As, 3.81 grams of sodium nitrate present in 1 liter of water

So, 5.40 grams of sodium nitrate present in $\frac{5.40}{3.81}=1.42$ liter of water

Therefore, the volume of water added must be, 1.42 L

Answer 2

 the concentration has been given as g/L. this is the mass of solute that can be dissolved in 1 L solution.
the concentration of the solution that needs to be prepared - 3.81 g/L
the mass of sodium nitrate is - 5.40 g
the  volume needed for 3.18 g  - 1 L
then the volume needed for 5.40 g - 1/3.18 x 5.40 
volume of water needed - 1.42 L