Chapter 9.4 Flashcards
1
Q
What is the definition of a colligative property
A
- they are physical properties of solutions
- > that are dependant on the concentration of dissolved particles
- > not on the chemical identity of the dissolved particles
- examples include:
- > osmotic pressure, vapor pressure depression, boiling point elevation, freezing point depression
2
Q
Describe Raoult-s law
A
- accounts for vapor pressure depression caused by solutes in a solution
- > as solute is added to a solvent, the vapor pressure of the solvent decreases proportionately
- note this is because as more solutes are added
- > the more they can block the evaporation of solvent molecules
- > but they can’t block the condensation
- > so the amount of gas molecules over the liquid decreases, decreasing the vapor pressure
3
Q
What are solutions that obey Raoult’s law referred to as
A
-they are referred to as ideal solutions
4
Q
How is boiling point affected by a solute dissolving in a solvent to create a solution
A
- boiling point is the temperature at which the vapor pressure equals the ambient pressure
- therefore, if adding solute to a solvent decrease vapor pressure
- > then boiling point needs to increase(more energy) to make the vapor pressure equal to the ambient pressure
5
Q
Describe the concept of freezing point of depression
A
- the presence of solute particles in a solution interferes with the formation of the lattice arrangement of solvent molecules associated with the solid state
- > thus a greater amount of energy must be removed from the solution in order for the solution to solidify
6
Q
What is the definition of osmotic pressure
A
- sucking pressure generated by solutions in which water is drawn from the solution
- > osmotic pressure is the amount of pressure that must be applied to counteract attraction of water molecules to the solution
