Topic 3 - Chemical Changes

Question 1

Define

Electrolysis.

Answer 1

the process of breaking down a substance using electricity

Question 2

Define

Electrolyte.

Answer 2

the liquid required for electrolysis which conducts electricity

electrolytes contain free ions

Question 3

Define

Electrode.

Answer 3

a solid that conducts electricity and is submerged in the electrolyte

Question 3

What reaction(s) occur during

electrolysis?

Answer 3

Redox
reduction is occuring at the negative electrode (as the positive ions are gaining electrons)
oxidation is occuring at the positive electrode (a the negative ions are losing electrons

Question 4

Define

Binary compound.

Answer 4

an ionic compound containing two elements which are ions - a positive metal ion and a negative non-metal ion

Question 5

What products are formed during the

electrolysis of molten binary compounds?

Answer 5

the neutral metal and non-metal elements

Question 6

What occurs at the cathode (negative electrode) during the

electrolysis of aqueous solutions?

Answer 6

Hydrogen will be produced unless the metal is less reactive than it. If the metal is less reactive, a solid layer of pure metal will be produced instead.

This is because the more reactive an element, the more likely it is to stay as ions.

Question 7

What is the

order of reactivity?

(18 elements)

Answer 7

Please - Potassium
Stop - Sodium
Lazily - Lithium
Calling - Calcium
Me - Magnesium
A - Aluminium
Careless - (Carbon)
Zebra - Zinc
Instead - Iron
Now - Nickel
Try - Tin
Learning - Lead
How - (Hydrogen)
Copper - Copper
May - Mercury
Save - Silver
Gold - Gold
Perfectly - Platinum

Question 8

What occurs at the anode (positive electrode) during the

electrolysis of aqueous solutions?

Answer 8

If halide ions are present then halide molecules will be formed. If not, then the hydroxide ions are reduced and oxygen and water are formed.

Question 9

Define

Inert electrode.

Answer 9

an electrode that does not participate in the chemical reactions