In: Chemistry
You prepare a solution by dissolving 50.4g sucrose (C12H22O11) in
0.332 kg of water. The final volume of the solution is 355 mL.
Calculate the concentration of the solution in each unit.
1 mole C12H22O11 = 342.296 g sucrose
(a) Molarity
(b) Molality
(c) Percent by mass
(d) Mole fraction
a)
number of moles of Sucrose = mass/molar mass
= 50.4 g / 342.296 g
= 0.147 mol
Volume = 0.355 L
Molarity = number of moles / Volume
= 0.147 mol / 0.355 L
= 0.415 M
b)
Molality = number of moles / mass of solvent in Kg
= 0.147 mol / 0.332 Kg
= 0.443 molal
c)
percent by mass = mass of solute *100 / total mass
= 50.4 *100 / (50.4 + 332)
= 13.2 %
d)
number of moles of water = mass/ molar mass = 332/18 =18.44
moles
Mole fraction = number of moles of solute / total
moles
= 0.147 / (0.147 + 18.44)
= 7.91*10^-3