Question 14 a student dissolves 1.5g of styrene c8h8 in 225.ml of a solvent with a density of 1.02/gml . the student notices that the volume of the solvent does not change when the styrene dissolves in it. calculate the molarity and molality of the student's solution. round both of your answers to 2 significant digits. molarity = molality = ă—10

Answers:

a. 0.064 mol/L; b. 0.063 mol/kg

Explanation:

a. Molar concentration

c = moles/litres

Moles = 1.5 × 1/104.15

Moles = 0.0144 mol

Litres = 225. × 1/1000

Litres = 0.225. L

c = 0.0144/0.225.

c = 0.064 mol·L⁻¹

b. Molal concentration

b = moles of solute/kilograms of solvent

Mass of solvent = 225. × 1.02/1

Mass of solvent = 229.5 g      Convert to kilograms

Mass of solvent = 0.2295 kg

b = 0.0144/0.2295

b = 0.063 mol/kg