How to Calculate CaCl2 Concentration from Vapor Pressure Data?

Click For Summary
SUMMARY

The discussion focuses on calculating the mass percent concentration of CaCl2 in an aqueous solution using vapor pressure data and Raoult's Law. Given a vapor pressure of 82.3 mmHg for the CaCl2 solution and 92.6 mmHg for pure water at 50 degrees C, the mole fraction of CaCl2 (x) and water (1-x) are established. By assuming a 1L solution with a density of 1 g/mL, participants derive equations to relate the mass of solute and solvent, ultimately leading to the calculation of mass percent concentration.

PREREQUISITES
  • Understanding of Raoult's Law
  • Knowledge of mole fraction calculations
  • Familiarity with mass percent formula
  • Basic principles of solution density
NEXT STEPS
  • Study Raoult's Law applications in different solute-solvent systems
  • Learn about vapor pressure lowering and its implications in colligative properties
  • Explore methods for calculating mass percent in various chemical solutions
  • Investigate the relationship between molarity and molality in solutions
USEFUL FOR

Chemistry students, educators, and professionals involved in solution chemistry and colligative properties analysis will benefit from this discussion.

Ki-nana18
Messages
90
Reaction score
0

Homework Statement



An aqueous CaCl2 solution has a vapor pressure of 82.3 mmHg at 50 degrees C. The vapor pressure of pure water at this temperature is 92.6 mmHg. What is the concentration of CaCl2 in mass percent?


Homework Equations


mass %=(mass of component/total mass)*100%
Psolution=XH2OPH2O


The Attempt at a Solution


I know I have to use Raoult's Law in order to compute the mole fraction but I'm not sure what to do after. Once I have mole fraction what do I do?
 
Physics news on Phys.org
Assume 1L of the solution. Molar fraction of CaCl2 is x, molar fraction of water is 1-x. Write definition of molar fraction, write how does the mass depend on number of moles for solvent and for solute. Mass of solvent plus mass of solute is a mass of 1L of solution. Assume density of 1 g/mL. That will give you a set of equations, you should be able to solve them for mass of solute and mass of solvent.
 

Similar threads

Replies
3
Views
2K
  • · Replies 36 ·
2
Replies
36
Views
8K
Replies
6
Views
11K
  • · Replies 0 ·
Replies
0
Views
1K
Replies
2
Views
3K
Replies
3
Views
4K
  • · Replies 6 ·
Replies
6
Views
2K
Replies
35
Views
5K
Replies
1
Views
3K
Replies
2
Views
9K