Lecture 6

Question 1

What is a electrolyte?

Answer 1

The electrolyte is the compound that is decomposed; it is either molten ionic compound or a concentrated aqueous solution of ions.

Question 2

What is electrolysis?

Answer 2

Electrolysis is the decomposition of a compound into its elements by an electric current.

Question 3

What are the uses of electrolysis?

Answer 3

Used to extract metals that are high in the reactivity series. Used to produce non-metals such as chlorine and to purify some metals.

Question 4

What are electrodes?

Answer 4

Electrodes are rods, made from either carbon or metal. which can conduct electricity to and from the electrolyte. The anode is positive and the cathode is negative.

Question 5

What power supply should electrolysis use\?

Answer 5

Direct current

Question 6

What forms at the cathode?

Answer 6

Either a metal or hydrogen forms. If a metal is more reactive than hydrogen, its ions stay in solution and hydrogen bubbles off. But if the metal is less reactive than hydrogen the metal forms.

Question 7

What is the order of most reactive metals to least reactive

Answer 7

Potassium
Sodium
Calcium
Magnesium
Aluminium
Zinc
Iron
Lead
Hydrogen
Copper
Silver

Question 8

What is the anode?

Answer 8

A non-metal other than hydrogen forms. If it is a concentrated solution of a halide the chlorine, bromine, iodine forms.

Question 9

If KBr solution is used what material should the cathode and anode be?

Answer 9

Cathode=hydrogen Anode=Bromine

Question 10

If AgNO3 solution is used what material should the cathode and anode be?

Answer 10

C=silver A=oxygen

Question 11

If HCl solution is used what material should the cathode and anode be?

Answer 11

C=hydrogen A=chlorine

Question 12

If NaCl solution is used what material should the cathode and anode be?

Answer 12

C=hydrogen A=chlorine

Question 13

Why is zinc used as a anode?

Answer 13

Because the alloy is less resistant to the saltwater’s electrolytes.

Question 14

What is brine?

Answer 14

Brine is a concentrated solution of sodium chloride.

Question 15

What is the symbol reaction of brine?

Answer 15

2NaCl + 2H2O = 2NaOH +Cl2 +H2

Question 16

Uses for Chlorine?

Answer 16

Plastic PVC, Medical drugs, paints and bleaches

Question 17

Uses for sodium hydroxide solution?

Answer 17

Soaps, detergents, paper and dyes.

Question 18

Uses of hydrogen?

Answer 18

Making nylon, make hydrogen peroxide and as a fuel in hydrogen fuel cells.

Question 19

What is electroplating?

Answer 19

Electroplating means using electricity to coat one metal with another, to make it look better or to prevent corrosion.

Question 20

Examples of electroplating

Answer 20

Steel car bumpers are coated with chromium. Steel cans are coated with tin to make tins for food.

Question 21

If you want to purify a metal by electrolysis, will you make it the anode or the cathode?

Answer 21

The cathode because the anode is made of impure metal and the cathode is made of pure copper. The anode dissolves to form metal ions.

Question 22

What is a salt bridge?

Answer 22

electrical neutrality within the internal circuit.
preventing the cell from taking its reaction to equilibrium.
Not used the reaction will likely continue

Question 23

What is an electrolytic cell?

Answer 23

An electrolytic cell is a type of electrochemical cell in which non-spontaneous redox reactions convert the electric energy to chemical energy.
The anode is the positive electrode and the cathode is the negative electrode.

Question 24

What is a electrochemical cell?

Answer 24

An electrochemical is a cell in which non-spontaneous redox reactions convert chemical energy into electrical energy or vice versa.
The cathode is the positive electrode and the anode is the negative electrode.

Question 25

What happens if the external potential applied is greater than the E cell of an electrochemical cell?

Answer 25

If the external potential applied is greater than the E cell of an electrochemical cell then the electrochemical cell behaves like an electrolytic cell. All the chemical reactions will be flipped and the electrical energy will be transformed into the chemical energy.

Question 26

What is a galvanic cell?

Answer 26

A galvanic cell is a cell in which spontaneous redox reactions convert chemical energy to electric energy.
In it, electric energy is generated by redox reactions.

Question 27

What is a primary cell?

Answer 27

A primary cell is a cell that is designed to be used once and discarded. In general, the electrochemical reaction occurring in the cell is not reversible, and so these cells cannot be recharged.
Examples of these Cells are dry Cells, Daniel Cells, etc.