Week 3 part 4

Question 1

What is reduction?

Answer 1

• The gain of electrons

Question 2

What is oxidation?

Answer 2

• The loss of electrons

Question 3

What is an ionic equation?

Answer 3

• Only the particles that react and the products they form are shown.
  e. g. Mg(s) + Zn^2(aq) = Mg^2(s) + Zn(s)

Question 4

What are spectator ions?

Answer 4

• Ions in an ionic equation that don’t change and they are of no interest.

Question 5

What is electrolysis?

Answer 5

• An electric current is passed through an electrolyte, the ions move towards the electrodes to form elements
• The metals will move towards the cathode because they form +ve ions and gain electrons (they are reduced)
• The non-metals will move towards the anode because they form -ve ions and lose electrons (they are oxidised)

Question 6

What is aluminium ore called

Answer 6

Bauxite

Question 7

What happens at the cathode in extracting aluminium?

Answer 7

• Al^3+ ions are attracted to the cathode where they pick up three electrons and become neutral and these sink to the bottom of the electrolysis tank.

Question 8

What happens at the anode in extracting aluminium?

Answer 8

• O^2- ions are attracted to the anode where they each lose two electrons and neutral oxygen will combine to form O2 molecules.

Question 9

What are the electrodes made of?

Answer 9

• Carbon so they need to be changed regularly as they combine with oxygen to form CO2.

Question 10

What happens at the cathode in aqueous solutions?

Answer 10

• if H+ ions and metal ions are present, hydrogen will be produced if the metal ions formed are more reactive than hydrogen. If the metal ions are less reactive than hydrogen, a solid layer of the pure metal will be produced instead.

Question 11

What happens at the anode in aqueous solutions?

Answer 11

• If OH- and halide ions are present, molecules of chlorine, bromine or iodine will be formed. If no halide ions are present, then the OH- ions are discharged and oxygen will be formed.

Question 12

What side of the battery should the wire lead to if it is connected to the anode?

Answer 12

The longer side

Question 13

What side of the battery should the wire lead to if it is connected to the cathode?

Answer 13

The shorter side

Question 14

What are the tests for chlorine, oxygen and carbon dioxide?

Answer 14

Chlorine - Bleaches litmus paper
Oxygen - Relights glowing splint
Carbon dioxide - Turns lime water foggy