Answer:
168°C is the melting point of your impure sample.
Explanation:
Melting point of pure camphor= T =179°C
Melting point of sample = [tex]T_f[/tex] = ?
Depression in freezing point = [tex]\Delta T_f[/tex]
Depression in freezing point is also given by formula:
[tex]\Delta T_f=i\times K_f\times m[/tex]
[tex]K_f[/tex] = The freezing point depression constant
m = molality of the sample = 0.275 mol/kg
i = van't Hoff factor
We have: [tex]K_f[/tex] = 40°C kg/mol
i = 1 ( non electrolyte)
[tex]\Delta T_f=1\times 40^oC kg/mol\times 0.275 mol/kg[/tex]
[tex]\Delta T_f=11^oC[/tex]
[tex]\Delta T_f=T- T_f[/tex]
[tex]T_f=T- \Delta T_f=179^oC-11^oC=168^oC[/tex]
168°C is the melting point of your impure sample.
