Lecture 2: Solutions And Their Behavior Flashcards
What is a solution?
A homogeneous mixture that consists of one or more solutes uniformly dispersed throughout a medium known as the solvent
Solvent
Present in the larger amount
Solute
Present in the smaller amount than the solvent
Molality (m)
Moles solute/kg solvent
Molarity (M)
Moles solute/L solution (more applicable to us)
Molality is never…
Equal to molarity
What is solubility?
Solubility is the amount of solute that will dissolve in a given amount of solvent
Saturated
A saturated solution contains the maximum amount of a solute, as defined by its solubility
Supersaturated
- this is NOT a stable system
- A solution contains more solute than allowed by the solubility
Miscible
Two liquids are miscible if they are soluble in each other in all proportions
(I.e.: alcohol is miscible in water; oil is not miscible in water)
Endothermic process
Energy flows into the system
Exothermic process
Energy flows out of the system
Heat
Transfer of energy into or out of a system caused by a difference in temperature
What is Henry’s Law?
As pressure increases for gaseous solutes, solubility increases
For liquid and solid solutes, P has…
A negligible effect
As temperature increases, solubility of a gaseous solute ___
Decreases
Example: think about opening a warm can of soda pop—the carbon dioxide is less soluble and comes bubbling out
As temperature increases, liquid and solid solubility ___
Increases
What is the effect of temperature on the amount of gas dissolved?
Inverse relationship—the colder the liquid (i.e.: blood), the more gas that will dissolve in the liquid
What does a colligative property depend on?
Depends only on the number of solute particles, not the identity of the solute particles
What are 4 colligative properties?
- The vapor pressure of a solution decreases with increasing solute concentration
- The boiling point of a solution increases with increasing solute concentration
- The freezing point of a solution decreases with increasing solute concentration
- The osmotic pressure of a solution increases with increasing solute concentration
Vapor pressure and increasing solute concentration
Decreases
Boiling point and increasing solute concentration
Increases
Freezing point and increasing solute concentration
Decreases
Osmotic pressure and increasing solute concentration
Increases
What is vapor pressure of a liquid?
Results from the most energetic molecules near the surface of the liquid escaping into the gas phase
The vapor pressure of a solution (solutes added) is ___ than the vapor pressure of the pure solvent
Less than
Raoult’s law
Gives the vapor pressure of a solution
Boiling point
The temperature at which the vapor pressure of the material is equal to the ambient pressure
Vapor pressure of a solution is decreased by…
The addition of nonvolatile solutes—a higher temperature is needed to drive the vapor pressure up to the point where it equals ambient pressure
What increases the boiling point of a solution?
An increase in the concentration of solutes
Freezing Point
The temperature at which the liquid phase of the material is in equilibrium with the solid phase
Tonicity
The relative concentration of solutes in osmotic systems
Isotonic =
Equal concentrations of particles
Hypertonic =
Greater concentration of solute
Hypotonic =
Lower concentration of solute
Osmosis
Diffusion of water
Diffusion occurs spontaneously from…
High concentration to low concentration
What are colloids?
Not true solutions
-Might be supersized molecules (i.e.: proteins) or aggregate ions
Colloidal particles cannot…
Be filtered and do not settle out of solution
Examples of colloids
- blood
- milk
- jelly
- albumin
