Metals and their properties, Electrolysis

What is electrolysis?

The breaking down of a substance using electricity.

What does OIL RIG stand for?

Oxidation Is Lost, Reduction Is Gained

Which ions are positive?

Cations

What do the cations do?

Move towards the cathode, negative electrode

What are anions?

negative ions

What is the name for a negative ion?

anion

What do the anions do?

Move towards the anode, positive electrode

What do half equations show?

How electrons are transferred during reactions

Give the steps to set up an electrochemical cell

Get two unreactive electrodes
Clean and don’t touch the part going into the solvent
Place both of them into a beaker with the electrolyte
Use crocodile clips to connect a power source to them

What actually happens if something is oxidised?

It gains oxygen and loses electrons

What is the base reaction for metals and water

metal +water —> metal hydroxide + hydrogen

What is a redox reaction?

when oxidation and reduction happen at the same time

For electrolysis to happen does the element have to be more or less reactive than Carbon?

More

REACTIVITY SERIES

K
Na
Li
Ca
Mg
Al
C
Zn
Fe
Sn
H
Cu
Ag
Au

What types of metals can be found uncombined in the earths crust? Give examples.

unreactive metals such as gold and platinum

Which metals have to be extracted and which need reduction?

Metals higher than Carbon must be extracted
Metals below Carbon need reduction

What is an electrolyte?

A liquid that contains an ionic compound and its ions are free to move

How do you make an electrolyte?

If it is soluble just dissolve it in water
If it is insoluble you must melt it into a molten liquid

What are electrodes usually made of?

Metal or Carbon

Why must the electrodes be joined with a wire?

So that the electrons can flow

What actually happens during electrolysis?

An electric current is sent from the power source through the electrolyte to the opposite electrode where they become neutral

What is the process of when the element reaches the opposite electrode and is made neutral called?

discharged

Which elements need electrolysis?

Any that are more reactive than Carbon

How do elements less reactive than carbon lose oxygen?

They form the half equation which makes the metal + carbon dioxide

Why don’t we use electrolysis for all elements?

It is very expensive as it takes a lot of energy

What do the ions have to be able to do in electrolysis for it to work?

they have to be able to move in order to allow electric current to pass through

What does inert mean?

It is unreactive