Question

How many grams of NaCl should be added to 250 grams of waterto
make a 0.40 m solution?

Answer 1

5.85 grams of NaCl should be added to 250 grams of water to make a 0.40 m solution.

Step-by-step explanation:

`molality=\frac{\text{Mass of solute}}{\text{Molar mass of solute}* \text{ Mass of solvent (kg)}}`

Mass of NaCl =x

Molar mass of NaCl = 58.5 g/mol

Molality of the solution = 0.40 m

Mass of the solvent = 250 g = 0.250 kg (1g = 0.001 kg)

`0.40 m=(x)/(58.5 g/mol* 0.250 kg)`

`x=0.40 m* 58.5 g/mol* 0.250 kg=5.85 g`

5.85 grams of NaCl should be added to 250 grams of water to make a 0.40 m solution.