What do the following state symbols mean?
Aqueous=dissolved in water
What are ions able to do when melted or dissolved in water?
What is electrolysis?
Using electricity to break up an ionic substance
During electrolysis what happens to the positive ions?
Attracted to the negative electrode
During electrolysis what happens to the negative ions?
Attracted to the positive electrode
What happens to the ions at the negative electrode?
Positive ions gain electrons
What happens to the ions at the positive electrode?
Negative ions lose electrons
What does OILRIG mean?
Oxidation is loss of electrons
Reduction is gain of electrons
What are the 3 products of the electrolysis of sodium chloride solution?
Sodium hydroxide, Chlorine, Hydrogen
Give one use of each product?
Sodium hydroxide =soap
Give the half equation for the reaction at the positive electrode?
2Cl- → Cl2 +2e-
Give the half equation for the reaction at the negative electrode?
2H+ + 2e-→ H2
How can copper be purified using electrolysis?
Use copper solution and 1 pure electrode and one impure electrode
What is electroplating?
Using electrolysis to add a thin layer of metal
What happens at the positive electrode in the electrolysis of aluminium oxide?
2O2- → O2 +4e-
What happens at the negative electrode in the electrolysis of aluminium oxide?
Al3+ + 3e-→Al
What is cryolite used for?
To lower the melting point of the aluminium oxide
What happens over time to the positive electrode in the electrolysis of aluminium oxide?
Carbon reacts with the oxygen to produce carbon dioxide and the electrode shrinks and has to be replaced.