C2.5 Salts and electrolysis

Question 1

If a substance is a base what ending of its name would it have?

Answer 1

Oxide or hydroxide

e.g. Copper oxide is a base

Question 2

What do all acids contain?

Answer 2

H+

Question 3

What do all bases contain?

Answer 3

OH-

Question 4

What do these letter mean in a equation?

• (s)
• (l)
• (g)
• (aq)

Answer 4

• (s) = solid
• (l) = liquid
• (g) = gas
• (aq) = aqueous (solid but now a liquid)

Question 5

What does a water and a base produce?

Answer 5

An alkali

Question 6

What does an acid and a base produce?

Answer 6

Salt and water

Question 7

What does an acid and a carbonate produce?

Answer 7

Salt and water and carbon dioxide

Question 8

What does a metal and an acid produce?

Answer 8

Salt and hydrogen

Question 9

What does a metal oxide and an acid produce?

Answer 9

Salt and water

Question 10

Describe how crystals of calcium chloride can be made from calcium carbonate and dilute hydrochloric acid {4}

Answer 10

1) Add an excessive amount of calcium carbonate to hydrochloric acid
2) It fizzes. wait for it to stop and then filter it into a beaker
3) Heat the substance till half of the liquid has evaporated and some crystals have started to form
4) Leave to cool and see if crystals form

Question 11

Define electrolyte

Answer 11

Ionic liquid or solution broken down by electrolysis

Question 12

What does PANIC stand for?

Answer 12

P- positive 
A- anode 
N- negative 
I- is 
C- cathode

Question 13

What does OIL RIG stand for?

Answer 13

O- oxidation
I- is
L- loss

R- reduction
I- is
G- gain

Question 14

What happens to the electrons at the cathode?

Answer 14

They are lost (oxidation)

Question 15

What happens to electrons at the anode?

Answer 15

It gains electrons (reduction)

Question 16

In a solution such as calcium fluoride what goes to the cathode and why?

Answer 16

Hydrogen
because it is less reactive than fluoride so it is displaces. The hydrogen is positive so it has to go to the cathode. Hydrogen comes from the water solution. Fluoride is more reactive so it reacts with the oxygen in the water

Question 17

During electroplating what goes at the cathode (negative)?

Answer 17

The object that needs to be coated

Question 18

During electroplating what goes at the anode (positive)?

Answer 18

The metal the object needs to be coated with

Question 19

During electroplating what should the electrolyte be (solution)?

Answer 19

a nitrate or sulphate of the metal that is coating the object e.g. copper nitrate/ copper sulphate

Question 20

Balance these half equations (number with star is small number)

1) Al3* + + e– → Al
2) Cl2*+ + e– → Cu

Answer 20

1) Al3*+ + 3e– → Al

2) Cu2*+ + 2e– → Cu