Chemistry Assignment: Vapour Pressure and Reverse Osmosis Study

This chemistry assignment solution addresses calculations related to vapour pressure, reverse osmosis, and the properties of ideal dilute solutions. The solution includes calculations for the vapour pressure of a solution containing bromine in carbon tetrachloride, considering Henry's law and mole fractions. It determines the total pressure and the composition of the vapour phase. Furthermore, the assignment explores the reverse osmosis process, calculating the minimum pressure required for seawater desalination. The solution also provides an analysis of the vapour pressure of a pure liquid and its relationship to temperature, utilizing the Clapeyron equation. The document provides a comprehensive understanding of the concepts and calculations involved in these chemical processes.

Chemistry
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Q3 (a) A dilute solution of bromine in carbon tetrachloride behaves as an ideal dilute solution.
The vapour pressure of pure CCl4CCl4 is 33.85 Torr at 298 K. The Henry's law constant when
the concentration of Br2Br2 is expressed as a mole fraction is 122.36 Torr. Calculate the vapour
pressure of each component, the total pressure, and the composition of the vapour phase when
the mole fraction of Br2Br2 is 0.050, on the assumption that the conditions of the ideal dilute
solution are satisfied at this concentration. (b) The vapour pressure of a pure liquid A is 23 kPa
at 20∘C20∘C and the Henry's law constant of B in liquid A is 73 kPa. Calculate the vapour
pressure of each component, the total pressure, and the composition of the vapour phase when
the mole fraction of B is 0.066 on the assumption that the conditions of the ideal-dilute solution
are satisfied at this concentration.
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Q4. The freezing point of seawater is−1.9 ℃. Reverse osmosis can be applied for the
desalination of seawater. Figure out the least pressure that should be applied on the seawater side
compartment to cause reverse osmosis at 20 ℃. Given that the freezing point depression constant
of water is1.86 K . kg mol−1, the density of water is1.0 ×103 kg m−3
SOLUTION
Seawater is approximately 0.60 M NaCl. What is the minimum pressure that must be
applied at 20 degrees Celsius to purify seawater by reverse osmosis
? Assume i=2.0
for NaCl.
Osmotic pressure=i MRT
R=gas constant=0.0821 Latm/mol K
Osmotic pressure=2.0 ×0 .60 M (0 .0821 Latm/mol K )(293 K )=28.86 Latm
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Q6. The vapour pressure of a liquid A at 40 ℃ is determined to be 24.00 kpa, and its
∆vap Hm=33.43 kJ .mol−1. Suppose ∆vap Hm is temperature independent and the vapour behaves
as ideal gas;
1) Calculate the vapour pressure of pure liquid at 6 0 ℃.
2) Calculate ∆ H and ∆ S for 2 mol A in the process(
I , 60 ℃ , 100 kpa ¿ →( g ,60 ℃ , 100 kpa)
Using the Clapeyron Equation
If the vapor is considered an ideal gas, then;
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