If you’re given molecular weight, you know that density is mass/volume. You need to convert the molecular weight to volume. If you know what molecule it is, use the gram formula mass to convert it into grams.
Answer:
222.2 grams of CaCl2 in 2 moles
Explanation:
Mole=given mass/gram mass formula
2moles=x/Gram Mass Formula
(Gram Mass Formula of CaCl2):
Ca=40.1
Cl= 35.5 x 2= 71
-----------------------
GFM=111.1
2 moles = x/111.1 g
x=222.2
First determine the molality of the solution. m = (w solute)/[(mm solute)(kg solvent)] -- mm means molar mass. So,
m = (14.7 g)/[(180 g/mol)(0.150 kg) =0.544 mol/kg = 0.544 m
Change in boiling point (∆t) = m x Kbp = (0.544 m)(0.512 °C/m) = 0.28°C
The solution will boil at 100.28°C at 1 atm.
the density if water is 1.00 g/ml and Kb= 0.512 C/m
