2. an aqueous solution of a certain organic compound has a density of 1.063 gml-1, an osmotic pressure of 12.16 atm at 250 c and a freezing point of -1.030 c. what is the molar mass of the compound? plzzz it's urgent plzzz plzzz plzzzz plzzzzzz plzzzzz
Answers
here is the ans .
hope it helps you
☺☺☺☺☺☺
Answer:
The molar mass of the compound will be 334 gmol⁻¹.
Calculation:
In order to calculate the molar mass of the compound, we will need to go through various steps using different formulas. The main ones are written below:
- Osmotic pressure → π = M × R × T
- Freezing point → ΔTf = Kf × m
- Molality →
In the question, the data given to us is:
- Osmotic pressure → 12.16 atm
- Density → 1.063 gml⁻¹
- Temperature → 25°C = 298.15 K
- Freezing point → -1.03 °C
- First, find out ΔTf:
ΔTf = ΔT°f - Tf
0° - (-1.03)
ΔTf = 1.03°C
- Second, find the molality with the freezing point formula.
ΔTf = Kf × m
The experimental value of Kf of water is 1.86°Ckg/mol.
1.03 = 1.86 × m
molality = 0.554 m
Third, using the osmotic pressure formula we find the molarity.
π = M × R × T
12.16 = M × 0.082 × 298.15
M =
Molarity = 0.479M
Fourth, find the mass of solvent using the formula, followed by mass of solution and mass of solute.
Mass of solvent =
Mass of solvent = 897 g
Mass of solution = 1.063 × 1000 = 1063 g
Mass of solute = 1063 - 987 = 166 g
At last, we use the molality formula to calculate the molar mass.
m= where
- W₂, mass of solute = 166 g
- M₂, mass of the compound
- m= molality = 0.554 M
- W₁, mass of solvent = 897 g
0.554 =
M₂ =
M₂ = 334 gmol⁻¹
Conclusion:
The molar mass is 334 gmol⁻¹.