Lecture 3 (Physical properties) Flashcards
What are the characteristics of Solutions?
- Transparent to light
- Does not separate on standing
- Non-filterable
What are the characteristics of Colloids?
- Murky/opaque to light
- Does not separate on standing
- Non-filterable
What are the characteristics of Heterogenous mixtures?
- Murky/opaque to light
- Separates on standing
- Filterable
What is a Homogenous mixture?
A uniform mixture that has the same composition throughout
What is a solution?
A homogenous mixture that contains particles the size of a typical ion or small molecule
What is a colloid?
A homogenous mixture that contains particles that range in diameter from 2 to 500nm
Why don’t oil and water mix?
Because they have different intermolecular forces
What are Solid hydrates?
Ionic compounds that attract water strongly enough to hold onto water molecules even when crystalline
What is the difference in effect of temperature on solubility in solids and gases?
SOLIDS: as temperature increases, solubility INCREASES
GASES: as temperature increases, solubility DECREASES
Define Henry’s law
The solubility (or concentration) of a gas is directly proportional to the partial pressure of the gas if temperature is constant
[concentration (C) divided by pressure (P) is constant when T is constant]
How do you calculate Molarity (M)?
Moles of solute / Volume of solution
How do you calculate Moles of solute?
Molarity X Volume of solution
How do you calculate Volume of solution?
Moles of solute / Molarity
What is a way of expressing percent concentration of a solution?
Weight/volume percent concentration
W/V% concentration = Mass of solute (g) / Volume of solution (mL) X 100
What is a way of expressing a volume of solute as a % of the volume of final solution?
Volume/volume percent concentration
V/V% concentration = Volume of solute (mL) / Volume of solution (mL) X 100
What is the Dilution factor?
The ratio of the initial and final solution volumes (V1/V2)
What is the difference between electrolytes and non-electrolytes?
ELECTROLYTES = dissolve in water and separate into ions forming solutions that are able to conduct electricity
NON-ELECTROLYTES = dissolve in water but as molecules not as ions -> solutions don’t conduct electricity
What is the difference between a strong electrolyte, weak electrolyte and a non-electrolyte?
Strong electrolyte = completely dissociates into ions in an aqueous solution
Weak electrolyte = forms mostly molecules and a few ions in an aqueous solution
Non-electrolyte = dissolves as molecules in an aqueous solution
What are the physical properties of solutions?
- VAPOR PRESSURE is lower for a solution than for a pure solvent
- BOILING POINT is higher for a solution than for a pure solvent
- FREEZING POINT is lower for a solution than for a pure solvent
- OSMOSIS occurs when a solution is separated from a pure solvent by a semipermeable membrane
What is osmolarity?
The sum of the molarities of all dissolved particles in 1.0 liter of solution
When are two liquids called Isotonic?
When they have the same osmolarity
How is dialysis linked to osmosis?
In dialysis, the membrane allows the passage of solvent and small dissolved molecules but prevents passage of proteins and larger particles -> used to remove metabolic waste products from blood
