Purifying MetalsPurifying Metals

Aims:

• Describe the purification of copper by electrolysis

• Draw a simple diagram to the show the method used to purify copper

• How do you get copper?

• What is it used for?

Purifying Copper Purifying Copper

IMPURE COPPER ANODE

PURE COPPER CATHODECopper sulphate

CuSO4 solution

PURIFYING COPPER

Cu2+

Cu

CuCu2+

Cu2+Copper atoms from impure copper are OXIDISED to copper ions

Copper ions transported from anode to cathode

Copper ions from impure copper are REDUCED to copper atoms

As the atoms of the impurities are not transported, the copper that builds up on the cathode is extremely pure.

IMPURE COPPER ANODE

PURE COPPER CATHODE

IMPURE COPPER ANODE

PURE COPPER CATHODE

Over time, the impure anode dissolves away and the impurities sink to the bottom. The pure cathode grows as more pure copper is deposited on it.

Why will the concentration of the solution stay the same?

Cl-

Cl-

Cl-

Cl- Na+ Na+

Na+ Na+

OILRIG

- ions LOSING electrons to become atoms is called ‘OXIDATION’ (even though oxygen may not be involved)

+ ions GAINING electrons to become atoms is called ‘REDUCTION’

Oxidation is loss, reduction is gain

‘OILRIG’

Purification: The half reactions

Anode (+ve electrode)

Cu(s) Cu2+(aq) + 2e-

Cathode (-ve electrode)

Cu2+(aq) + 2e- Cu(s)

Oxidation Is Loss of electrons, Reduction Is Gain (OILRIG)

• Copper is purified to improve its NOT CIVIC DUTY

• Copper is purified by CELERY IS LOST

• Pure copper forms at the DO TEACH

• Impurities form called A ODD MENU

• The anode will slowly DIVE LOSS

• At the cathode copper ions gain CORN STEEL

conductivity

electrolysis

cathode

anode mud

dissolve

electrons

Unscramble the words to end the sentences