Question

A student is told to use 20.0 g of sodium chloride to make an aqueous solution that has a concentration of 10.0 g/L (grams of sodium chloride per liter of solution). Assuming that 20.0 g of sodium chloride has a volume of 7.50 mL, show that she will need about 1.99 L of water to make this solution. In making this solution, should she add the solute to the solvent or the solvent to the solute?

Answer 1

Answer:

she should add solute to the solvent

Explanation:

Given data :

Mass of the sodium chloride, = 20.0 g

Concentration of the solution = 10 g/L

Volume of 20.0 g of sodium chloride = 7.50 mL

Now, from the concentration, we can conclude that for 10 g of sodium chloride volume of the solution is 1 L

thus, for 20 g of sodium chloride  volume of the solution is 2 L or 2000 mL

also,

Volume of solution = Volume of solute(sodium chloride) + volume of solvent (water)

thus,

2000 mL = 7.5 mL + volume of solvent (water)

or

volume of water = (2000 - 7.5) mL

or

volume of water = 1992.5 mL

or

volume of water = 199.25 L ≈ 199 L

Answer 2

Explanation:

Concentration of sodium chloride = 10.0 g/L

1 Liters of solution has 10 g of sodium chloride

The volume of solution in which 20 g of sodium chloride will present is:

$\frac{1 L}{10 }\times 20 =2 L$

Volume of solution we will be making is of 2 L.

Volume of 20 g of sodium chloride = 7.50 ml = 0.00750 L

Volume of the water = ?

Volume of solution = Volume of solute + Volume of solvent

Volume of solvent = 2L - 0.00750 L = 1.9925 L

So,volume of water required to prepare the 2 L of 10 g/L solution of sodium chloride is 1.9925 L.

And for while making of the solution , student must add solute the solvent.