Question

What is the molality of a solution containing 30.0 g of napthalalene (C10H8) dissolved in 500.0 g of toulene? Please provide work. Thanks in advance!

Answer 1

Answer:

0.468 m

Explanation:

From the question given above, the following data were obtained:

Mass of napthalalene (C₁₀H₈) = 30 g

Mass of toulene = 500 g

Molality =?

Next, we shall determine the number of mole in 30 g of C₁₀H₈. This can be obtained as follow:

Mass of C₁₀H₈ = 30 g

Molar mass of C₁₀H₈ = (12×10) + (8×1)

= 120 + 8

= 128 g/mol

Mole of C₁₀H₈ =?

Mole = mass / molar mass

Mole of C₁₀H₈ = 30 / 128

Mole of C₁₀H₈ = 0.234 mole

Next, we shall convert 500.0 g of toulene to Kg. This can be obtained as follow:

1000 g = 1 Kg

Therefore,

500 g = 500 g × 1 Kg / 1000 g

500 g = 0.5 Kg

Finally, we shall determine the molality of the solution. This can be obtained as follow:

Mole of solute (C₁₀H₈) = 0.234 mole

Mass of solvent (toulene) = 0.5 Kg

Molality =?

Molality = mole of solute / Kg of solvent

Molality = 0.234 / 0.5

Molality = 0.468 m