COLLIGATIVE PROPERTIES Flashcards
1
Q
- What is a Solute?
A
- the dissolved substance
2
Q
- What is a Solvent?
A
- the substance that is doing the dissolving
3
Q
- In solid-liquids solutions, what is the solute and what is the solvent?
A
- the solute is the solid that dissolves in the solvent
- the solvent is a liquid
4
Q
- In liquid-liquid solutions, what is the solute and what is the solvent?
A
- the solute is the liquid found in the smaller amount
- the solvent is the liquid that is present in higher
amounts
5
Q
- What is meant by “Like dissolves like”?
A
- polar solvents dissolve polar solutes
- non-polar solutes dissolve in non-polar solvents
EG: water and oil are not an example of like dissolves
like
: water is polar
: oil is non-polar
: the one cannot dissolve in the other
6
Q
- What are the two units of concentration we focus on in this topic?
A
- Mole Fraction (X)
- Molality (m)
7
Q
- What is Molarity defined as?
A
- it is the moles of the solute
DIVIDED - by the litres of the solution
- the litres of the solution consist of the volume of the solute and the volume of the solvent mixed together
8
Q
- What are the advantages of Molarity (M)?
A
- it is convenient for titrations
- it makes use of simpler stoichiometric calculations
9
Q
- What are the disadvantages of Molarity (M)?
A
- it is dependent on temperature
- this is because the volume of the solution is involved in
the equation - it will only be valid for the temperature that the
solution was made at
10
Q
- What is the Mole Fraction (X) defined as?
A
- it is the moles of the component
DIVIDED - by the total moles in the solution
11
Q
- What are the advantages of the Mole Fraction (X)?
A
- it is independent of temperature
- it does not depend on the volume of the solution
- it is convenient for gas mixtures
- it can also be used for liquid-liquid solutions
12
Q
- What is Molality (m) defined as?
A
- it is the moles of the solute
DIVIDED
by the kilograms of the solvent
13
Q
- What are the advantages of Molality (m)?
A
- it is independent of temperature
14
Q
- What unit is often used to convert to Molarity (M)?
A
- the density of a solution
15
Q
- When are Molarity and Molality similar?
A
- when the dilute water solutions are similar
16
Q
- When are Molarity and Molality different?
A
- when you use a solvent with a very different density from water
17
Q
- What does 1 Litre of water weigh?
A
- it weights 1kg
- 1000 grams
18
Q
- What is the derivative of the word Colligative?
A
- the word has a latin origin
- it means the number/amount of particles
19
Q
- What do Colligative Properties depend on?
A
- they depend on the amount (number of particles) of the solute that is placed on the solution
- they do not depend on the type of solute
- the more particles present in the solute:
- the greater the effect of the colligative properties
20
Q
- What are 4 Colligative Properties?
A
- Vapour Pressure Lowering
- Boiling Point Elevation
- Freezing Point Depression
- Osmotic Pressure
21
Q
- The left flask has a lid on top of it.
It is a closed container.
it contains pure water.
What happens to the water inside under normal circumstances?
A
- some water molecules will evaporate
- they will float above the liquid surface
- this creates a small vapour pressure
22
Q
- The flask on the right contains a water and sugar
solution.
What do the pink particles in the image represent?
A
- the sugar molecules
23
Q
- What exists in the sugar and water solution?
What is the result of these?
A
- intermolecular forces
(ion dipole forces) - these are found between the sugar and the water molecules
- these forces make it difficult for the water molecules to
exit the liquid phase - the rate of the evaporation decreases