Chemistry- Separating substances

HideShow resource information
  • Created by: Kitsune
  • Created on: 28-06-16 19:02
What is a mixture?
It contains more than one substance that are not chemically combined
1 of 37
What is a solute?
Something that is dissolved
2 of 37
Why is the solubility of every substance different?
Because all particles are different
3 of 37
What happens to solubility when temperature rises?
It increases
4 of 37
What does saturated mean?
A solution can't dissolve more solute at that temperature
5 of 37
What is a solution in water called?
Aqueous solution
6 of 37
What does volatile mean?
A liquid that evaporates easily
7 of 37
What does ethanol dissolve?
Glues, printing inks
8 of 37
Why are some substances volatile?
The forces between the particles are very weak
9 of 37
What is a pure substance?
It doesn't have any other substances mixed with it
10 of 37
Why do some substances need to be pure?
Impurities can be harmful to humans
11 of 37
Which substances need to be pure?
Medical drugs and food flavourings
12 of 37
What is an impurity?
An unwanted substance mixed with the substance you want
13 of 37
How to check for purity?
Check melting and boiling points because a pure substance has a sharp definite pair of them
14 of 37
What happens when an impurity is present?
The melting point falls and the boiling point rises; melting and boiling occurs over a range of temperatures
15 of 37
What is used to separate an insoluble solid from a liquid?
Filtration
16 of 37
What is the trapped solid in filtration?
Residue
17 of 37
What is the clear liquid from filtration called?
Filtrate
18 of 37
What is used to separate a soluble solid from a liquid?
Crystallisation or evaporation of the solvent
19 of 37
Why is evaporation of the solvent used instead of crystallisation?
For some substances solubility changes very little so there is no point is crystallisation
20 of 37
How to separate two solids in a mixture?
Choose a solvent that dissolves only one of them and remove the other by filtration
21 of 37
What is used to separate a solvent from a mixture?
Simple distillation
22 of 37
What is the point of a condenser?
To help vapour condense
23 of 37
What is used to separate a mixture of gases?
Fractional distillation
24 of 37
Why does fractional distillation work?
It takes advantage of the different boiling points
25 of 37
What do the vapours in fractional distillation go through before they reach the condenser?
Glass beads
26 of 37
Where is fractional distillation used?
In petroleum industry to refine crude oil, in production of ethanol, to separate the gases in air
27 of 37
What is used to separate pigments and amino acids?
Paper chromatography
28 of 37
Why do the substances in paper chromatography separate?
They have different solubility
29 of 37
What does the solubility depend on in paper chromatography?
The paper and the solvent
30 of 37
Which substance will travel further on the chromatogram?
The most soluble one
31 of 37
What is paper chromatography used for?
Identification/separation/purification of substances, checking purity, detective work
32 of 37
What is the solvent for amino acids?
Water+ethanoic acid+butanol
33 of 37
What is used to make amino acids visible?
Locating or fixating agent
34 of 37
How to find the Rf value?
Distance moved by substance divided by distance moved by solvent
35 of 37
What is the Rf value for the same substance?
It is the same under the same conditions and the same solvent
36 of 37
What two phases are there in chromatography?
Stationary and mobile
37 of 37

Other cards in this set

Card 2

Front

What is a solute?

Back

Something that is dissolved

Card 3

Front

Why is the solubility of every substance different?

Back

Preview of the front of card 3

Card 4

Front

What happens to solubility when temperature rises?

Back

Preview of the front of card 4

Card 5

Front

What does saturated mean?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all Separating substances resources »