C6

Question 1

What is an electrolyte?

Answer 1

An electrolyte is just a liquid or solution that can conduct electricity.

Question 2

What is an electrode?

Answer 2

An electrode is a solid that conducts electricity and is submerged in the electrolyte

Question 3

During electrolysis, where does an electric current pass through

Answer 3

An electrolyte. The ions move towards the electrodes, where they react, and the compound decomposes

Question 4

The positive ions in the electrolytewill move towards the _______ (-ve electrode) and gain electrons (they are __________). The megative ions in the electrolyte more towards the ______ (ve+ electrode) and lose electrons (they are __________)

Answer 4

Cathode, reduced
Anode, oxidised

Question 5

As ions gain or lose electrons, they form the _____________ _____________ and are _______ from the electrolyte

Answer 5

Uncharged element, discharged

Question 6

The ionic compound that is broken down by an electric current in electrolysis is called the

Answer 6

Electrolyte

Question 7

In electrolysis, why do positively charged ions move to the negstive electrode and the negative ions move towards the positive electrode

Answer 7

As opposite charges attract

Question 8

Can ionic compounds be electrolysed? If not why

Answer 8

Because ions are in fixed positions and can’t move

Question 9

Molten ionic compounds can or cannot be electrolysed

Answer 9

They can as the ions can move freely and conduct electricity

Question 10

Molten ionic liquids (lead bromide, are always broken up into their elements. Positive metal ions are reduced to the element at the csthode:

Negative non-metal ions are oxidised to the element at the anode:

Answer 10

Pb2+ + 2e- ~ Pb

2Br- ~ Br2 + 2e-

Question 11

Extracting metals using electrolysis is:

Answer 11

Very expensive aslots of energy is required to melt the ore and produce the reauired current.

Question 12

The extraction of aluminium from its ore by using electrolysis

Answer 12

-It is extracted from the ore Baixite by electrolysis. Contains aluminium oxide.
- aluminium oxide has very high melting temperature so it’s mixed with cryolite to lower the melting point
- the molten mixture contains free ions - so it’ll conduct electricity.

-the positive Al3+ ions are attracted to the negstive electrode where they each pick up three electrons and turn into nuetral aluminium atoms. These then sink to the bottom of the electrolysis tank

• the negative O2- ions are attracted to the positive electrode where they each lose two electrons, the nuetral oxygen atoms will then combine to form o2 molecules

Question 13

EXTRACTION OF ALUMINIUM FROM BAUXITE BY ELECTROLYSIS

Answer 13

INSERT PIC from pahe 58 cgp

Question 14

In aqueous solutions, as well as the ions from the ionic compound, there will be

Answer 14

Hydrogen ions and hydroxide ions from the water

Question 15

At the cathode, if H+ ions and metal ions are present, ________ ____ will be produced if the metal ions form an elementsl metal that is _____ reactive than hydrogen. If the metal ions form an elemental metal that is _____ reactive than hydrogen, a solid layer of the _____ ______ will be produced

Answer 15

Hydrogen gas, more, less, pure metal

Question 16

At the ______, if OH- and halide ions are present, molecules of chlorine, bromine or iodine will be formed. If no ______ _____ are present, then the OH- ions are discharged and ______ will be formed

Answer 16

Anode, halide ions, oxygen

Question 17

What do half equations show?

Answer 17

They show the reactions at the electrodes.

Question 18

One thing you must remember when combining half equations is?

Answer 18

The number of electrons needs to be the same for each half equation. Insert example from page 59 bottom of page

Question 19

What happens to chlorine, hydrogen and oxygen in experiments?

Answer 19

Chlorine bleaches damp litmus paper, turning it white, hydrogen makes a squeaky pop with a lighted splint, oxygen will relight a glowing splint

Question 20

A solution of copper (II) sulfate contains four different ions:

Answer 20

Cu2+, SO4 2-, H+ and OH-

Question 21

Copper metal is _____ reactive than hydrogen so

Answer 21

Less
At the cathode, copper metal is produced and coats the electrode
INSERT PIC OF CUSO4 SOLUTION IN ELECTROLYSIS PAGE 59

Question 22

(Copper sulfste solution is electrolysis)
There aren’t any halide ions present. So at the anode oxygen and water are

Answer 22

Produced. The oxygen can be seen as bubbles.

Question 23

A solution of sodium chloride (NaCl) contains four different ions:

Answer 23

Na+, Cl-, OH-, H+
Insert pic of NaCl solution in page 59 electrolysis

Question 24

Copper metal is ____ reactive than hydrogen. So at the cathode, _________ ____ is produced.

Answer 24

More, hydrogen gas.

Question 25

Electrolysis of aqueous solution sodium chloride
Chloride ions are present in the solution. So at the ______ chlorine gas is produced

Answer 25

Anode