Question

What is the molality of a solution made by dissolving 15.20 g of i2 in 1.33 mol of diethyl ether, (ch3ch2)2o?

Answer 1

The  molarity   of solution  made  by  dissolving  15.20g  of i2  in 1.33 mol  of diethyl ether (CH3CH2)2O  is    =0.6M

   calculation

molarity  =moles of solute/  Kg of the  solvent

mole  of the solute  (i2)  =  mass /molar mass
the molar mass of i2 = 126.9 x2 = 253.8 g/mol

moles is therefore=  15.2 g/253.8 g/mol  =  0.06  moles


calculate the Kg of solvent  (CH3CH2)2O
mass =  moles  x  molar mass
molar mass  of  (CH3CH2)2O= 74 g/mol

mass  is therefore = 1.33 moles  x  74 g/mol =  98.42 grams
in Kg = 98.42 /1000 =0.09842  Kg

molarity  is therefore = 0.06/0.09842 = 0.6 M