Solutions umledu解决的方案 umledu.ppt

Solutions umledu解决的方案 umledu
Solution Concentration
Although molarity (M) is used for stoichiometry calculations, tns
Ideal solutions typically involve non-polar molecules with similar structures. Mixtures of liquid hydrocarbons often form ideal solutions.
Liquid-Liquid Solutions
If the two components of the mixture are strongly attracted to each other, such as two polar molecules, the vapor pressure of the mixture is often less than that predicted by Raoult’s law.
Liquid-Liquid Solutions
This is known as a negative deviation from Raoult’s law. It occurs with mixtures of liquid acids and water. As the acid ionizes, the forces of attraction in the mixture increase.
Liquid-Liquid Solutions
If a mixture contains liquids that have stronger attractive forces when pure than when mixed, the mixture will exert a vapor pressure that is greater than that predicted by Raoult’s law. This is called a positive deviation from Raoult’s law.
Liquid-Liquid Solutions
A mixture of ethanol and water exhibits a positive deviation from Raoult’s law. The hydrogen bonding of each pure liquid is disrupted when the two liquids are mixed.
Pressure Effects
Gases dissolved in a liquid solute obey Henry’s Law:
C = kP
where C is the concentration, k is a constant specific to solute and solvent, and P is the pressure of the gas above the solution
Pressure Effects
Gases dissolved in a liquid solute obey Henry’s Law:
C = kP
The amount of a gas dissolved in a solution is directly proportional to the pressure of the gas above the solution.
Pressure Effects
Temperature Effects
For gases dissolved in liquids, the solubility decreases as temperature increases. That is, gases dissolve better in cold liquids than in warmer liquids.
Temperature Effects
For solid solutes dissolved in water, the effect of temperature on solubility is difficult to predict.
The Colligative Properties
The colligative properties are properties that depe