C2.7 Electrolysis

Question 1

What is the brief process of electrolysis?

Answer 1

Passing an electric CURRENT THROUGH ionic SUBSTANCES (molten/aq) to break them down INTO ELEMENTS

Question 2

What is the substance that is broken down called?

Answer 2

The electrolyte

Question 3

Electrolysis is used to electroplate objects. Give two examples of plating

Answer 3

• Copper plating

- Silver plating

Question 4

What happens to positively charged electrons at the negative electrode?

Answer 4

Positively charged ions GAIN ELECTRONS (reduction)

Question 5

What happens to negatively charged electrons at the positive electrode?

Answer 5

Negatively charged ions LOSE ELECTRONS (oxidation)

Question 6

If there is a mixture of ions, what do the products formed depend on?

Answer 6

The REACTIVITY of the elements involved

LEAST REACTIVE FORMS

Question 7

Reactions at electrodes can be represented by half equations. True or False?

Answer 7

True

Question 8

Complete the half equation:

2CL- —> CL2 + ___

Answer 8

+ 2e-

Question 9

How is aluminium manufactured? Describe.

Answer 9

• Electrolysis of a molten mixture of Al2O3 and cryolite

- Al at cathode, O at anode

Question 10

What is the positive electrode made from in the electrolysis of aluminium oxide? What happens to it?

Answer 10

• Carbon

- Reacts w/ O –> CO2

Question 11

What are the products of the electrolysis of sodium chloride solution?

Answer 11

• Hydrogen gas
• Chlorine gas
• Sodium hydroxide solution

Question 12

What can the products of the electrolysis of NaCl(aq) be used for?

Answer 12

• NaOH makes soap

- Chlorine= bleach and plastics