Question

A solution of 9.95 g of anhydrous aluminum chloride (AICI,) in 53.24 g of water freezes at -10.4 °C.

°C
K, (AICI,) = 1.86
Part 1 of 3
Calculate the molar mass of AICI, from the formula. Round your answer to the hundredths place.
0.9
Part 2 of 3
mol
Part 3 of 3
Calculate the molar mass from the freezing point depression, assuming AICI, does not dissociate in ions. Round your answer to 3 significant digits.
mol
X
ions
X
3
Comparing the two values, how many ions will AICI, form? Round your answer to the nearest whole number.
X
3

Answer 1

The molar mass in both cases are; 134 g/mol and 33 g/mol

What is the freezing point?

The freezing point of a substance is the temperature at which it transitions from a liquid phase to a solid phase under normal atmospheric pressure. At the freezing point, the substance undergoes a phase change from a more disordered and mobile liquid state to a more ordered and rigid solid state.

The molar mass is;

27 + 3(35.5)

= 133.5 g/mol

Then;

ΔT = 0 - (-10.4)

= 10.4

ΔT = K m i

m = moles/mass of solution in Kg

10.4 = 1.86 * 9.95/M * 1/0.05324 * 1

10.4 = 18.507/0.05324 M

M =18.507/ 10.4 * 0.05324

= 33.4 g/mol