C2 experimental techniques

Question 1

Filtration

Answer 1

Separates mixtures of insoluble solids and liquids

Question 2

Filtration process

Answer 2

• Mixture poured through filter paper
• Insoluble solid is trapped while the liquid(filtrate) runs through the paper and is collected below

Question 3

Chromatography

Answer 3

A process that separates a mixture into its different components depending on how they interact with chromatograph paper and solvent used

Question 4

Chromatography process

Answer 4

• Drops of solutions are placed near the bottom of a piece of chromatography paper along a line
• Paper is stood in a suitable solvent
• The solvent moves up the paper and carries the solutes in the solution with it

Question 5

Crystallisation

Answer 5

Separates a solute from its solution

Question 6

Crystallisation process

Answer 6

• Mixture is heated so that the solvent evaporates
• Crystals of the solute will form as the temp. falls

Question 7

Simple distillation

Answer 7

Used to separate a solvent from a solution

Question 8

Simple distillation process

Answer 8

• Mixture is heated until the liquid with the lower boiling point starts to boil
• Vapour released passes through a condenser where the gas cools back into a liquid

Question 9

Fractional distillation process

Answer 9

• Mixture is slowly heated until the liquids boil
• The vapor released rises up the fractioning column where it condenses on the glass beads (making them hot)
• When the beads reach a certain temp. the liquid with the lowest boiling point no longer condenses so it goes into the condenser
• Then it condenses and turns back into a liquid

Question 10

Fractional distillation

Answer 10

Separates a mixture of liquids from each other

Question 11

What does chromatography result in

Answer 11

A chromatogram

Question 12

The more soluble a substance is in the solvent, the ___ it will travel up the chromatography paper

Answer 12

Further

Question 13

Paper chromatograph can be used to

Answer 13

• Identify a substance
• Separate mixtures of substances
• Purify a substance by separating it from its impurities

Question 14

Rf value

Answer 14

The ratio of the distance travelled by the solute to the distance travelled by the solvent

Question 15

Rf value equation

Answer 15

Rf value = distance travelled by substance X/distance travelled by solvent

Question 16

Impurity

Answer 16

An unwanted substance mixed with the substance you want

Question 17

When a substance contains an impurity:

Answer 17

• Its melting point falls and boiling point rises
• It melts and boils over a range of temp. (not sharply)

Question 18

The more impurity there is:

Answer 18

• The bigger the change in melting and boiling points
• The wider the temp. range over which melting and boiling occur