Question

Student prepares a 0.207 g sample of the nonvolatile solute caryophyllene by dissolving the substance in 1.00 g of chloroform (Kb = 3.63C/m). The boiling point of chloroform increases by 3.68C. Determine the molar mass (g/mol) of caryophyllene?

Answer 1

Answer: 204.2 g/mol

Step-by-step explanation:

Elevation in boiling point is given by:

`\Delta T_b=k_b* m`

`\Delta T_b` = Elevation in boiling point =
`3.68^0C/m`

`k_b` = boiling point constant =
`3.63^0C/m`

m = molality

`Molality=(n* 1000)/(W_s)`

where,

n = moles of solute =
`\text {given mass}{\text {molar mass}}=(0.207)/(M)`

`W_s` = weight of solvent in g = 1g

Molality =
`(0.207* 1000)/(M* 1g)`

Putting in the values we get,

`3.68=3.63* (0.207* 1000)/(M* 1g)`

`M=204.2g/mol`

The molar mass of caryophyllene is 204.2 g/mol.