What is the molality of benzene in a solution that contains #"6.502 g"# of benzene in #"162.7 g"# of chloroform/#"CHCl"_3# (#K_f# for #"CHCl"_3# is #4.68^@ "C"cdot"kg/mol"# and #T_f^"*"# of #"CHCl"_3# is #63.5^@ "C"#)?

1 Answer

Answer:

Molality is defined as moles of solute per #"1 kg = 1000 g"# of solvent. Convert benzene's mass to moles, then divide by the mass of the solvent in kilograms.

Explanation:

#"6.0502 g" * ("1 mol")/("78.114 g") = "0.083238 moles"#

So

#"molality" = "0.083238 moles"/(162.7 * 10^(-3) " kg") = "0.51156 mol kg"^(-1)#