Question

g 250. mL of a solution is created and has a molarity of 1.50 M. What is the molality of this solution if the volume and density of the pure solvent is about the same as the volume and density of the final solution and the density of the pure solvent is 1.15 g/mL

Answer 1

1.30 m

Step-by-step explanation:

First we calculate the number of moles of solute in the solution, using the definition of molarity:

• Molarity = moles / liters

• Converting 250 mL ⇒ 250 / 1000 = 0.250 L

• moles = 1.50 M * 0.250 L = 0.375 moles

Then we calculate the mass of solvent, using the given volume and density:

• 1.15 g/mL * 250 mL = 287.5 g

• Converting 287.5 g to kg ⇒ 287.5 / 1000 = 0.2875 kg

Now we calculate the molality of the solution:

• molality = moles of solute / kg of solvent = 0.375 mol / 0.2875 kg

• molality = 1.30 m