Question #5a076

1 Answer
Jun 6, 2017

37,1 mol


cryoscopy says: the decrease of melting point is proportional to the molality (Tf-Tf°) = kf m.
#m = ((5,5-2°)C)/ (5,12 (°C)/(mol))=0,683 mol #
that means 0,683 mol of I2 in 1000 g of benzene.
You have 2,10 mol of I2, so you must have #(1000g)(2,10)/(0,683)= 3072 g# of benzene.
Since 1 mol of benzene weighs 78 g you need #(3072g)/(78g/(mol))=37,1 mol# of benzene