[dirknathan]

68.0 g of a solute were dissolved in 393 mL of benzene.  The solution froze at -0.50 °C. The normal freezing point of benzene is 5.5 °C and the molar freezing point constant is 5.12° kg/mol.  The density of benzene is 0.879 g/mL.  Calculate the molar mass of the solute.

Don't really know where to begin?

Don't recall ever needing to know freezing points to find molar mass!

[Borek]

Have you heard about freezing point depression?

Don't recall ever needing to know freezing points to find molar mass!

Now you know it can be used.

Or rather you will know once you will solve the problem 

[Hunter2]

68.0 g of a solute were dissolved in 393 mL of benzene.  The solution froze at -0.50 °C. The normal freezing point of benzene is 5.5 °C and the molar freezing point constant is 5.12° kg/mol.  The density of benzene is 0.879 g/mL.  Calculate the molar mass of the solute.

Don't really know where to begin?

Don't recall ever needing to know freezing points to find molar mass!

Something may help you here:

https://www.google.com/search?q=molar+mass+detemine+freezing+point&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a

[dirknathan]

Thanks the help.  I did eventually figure this one out.  I just asked my self, have The amount of the solute, what can be used with that to find molar mass?  I got it.