Respuesta :
Answer:
2.556.
Explanation:
Freezing point depression is defined as the decrease in temperature when a solute is added to a solvent.
The resulting liquid solution has a lower freezing point than the pure solvent because the chemical potential of the solvent in the mixture is lower than that of the pure solvent, the difference between the two being proportional to the natural logarithm of the mole fraction.
Mathematically,
ΔTf = Kf * b * i
where:
ΔTemp.f = the freezing-point depression. It is defined as Temp.f1 (pure solvent) − Temp.f2 (solution).
Kf = the cryoscopic constant, which is dependent on the properties of solvent.
b = the molality (moles solute per kilogram of solvent)
i = van 't Hoff factor
Kf = 1.853 K·kg/mol
Temp.f1 = 0°C
Temp.f2 = -3.60 °C
b = 0.76 m
ΔTf = Kf * b * i
0 - (-3.6) = 1.853 * 0.76 *i
i = 3.6/1.4083
= 2.556
Answer:
The van't Hoff factor is 2.55
Explanation:
Step 1: Data given
molality = 0.760 molal
The aqueous solution freezes at -3.60 °C
Kb of water = 1.86°C/m
Step 2: Calculate the van't Hoff factor
ΔT = i*Kb*m
3.60 = i * 1.86 * 0.760
i = 3.60( 1.86*0.760)
i = 2.55
The van't Hoff factor is 2.55
