Question

Calculate the molality of a solution formed by adding 26.0 g NaCl to 74.0 g of water at 10.0 °C. The density of this solution is 1.203 g/mL at 10.0 °C. The molar mass of NaCl = 58.44 g/mol and the molar mass of H2O = 18.02 g/mol.

Answer 1

Molality for the solution is 6.01 m/kg

Step-by-step explanation:

Molality means moles of solute in 1kg of solvent.

The solute is NaCl.

The solvent is H₂O.

Let's prepare the rule of three

In 74 g of solvent, there are 26 g of NaCl

In 1000 g of solvent, there are (1000 .26)/ 74 = 351.35 g

Let's convert this mass in moles.

Mass / Molar mass = moles

351.35 g /58.44 g/m = 6.01 moles