Question

A student dissolves 9.6g of styrene in of a solvent with a density of . 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 significant digits.

Answer 1

Molarity = 0.06 mol/L

Molality = 0.063

Step-by-step explanation:

Complete question

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

Solution

We must to know:

Molarity is equal to no. of moles divided by volume of solution

No. of moles = Mass/Molecular Mass

No. of moles of C8H8 = 1.5/104 = 0.0144

Molarity = 0.0144/225 = 0.06 mol/L

Molality = no. of moles / mass of solvent

Substituting the given values, we get -

Density = mass / V

Mass = density x V

1.02 * 225

= 229.5 g

Molality = 0.0144 / 229.5

0.063