CH1

Question 1

Definition of Redox reaction

Answer 1

A chemical reaction where oxidation and reduction occur at the same time

Question 2

Reduction in term of Oxygen

Answer 2

Loses oxygen

Question 3

Reduction in term of Hydrogen

Answer 3

gain hydrogen

Question 4

Reduction in term of Oxidation number

Answer 4

Oxidation number decrease

Question 5

Reduction in term of electron transfer

Answer 5

Gain electrons

Question 6

Oxidation in term of Oxygen

Answer 6

Gains oxygen

Question 7

Oxidation in term of Hydrogen

Answer 7

Loses hydrogen

Question 8

Oxidation in term of Oxidation number

Answer 8

Oxidation number increases

Question 9

Oxidation in term of electron transfer

Answer 9

loses electron

Question 10

Oxidation number of Oxygen in peroxides

Answer 10

-1

Question 11

Oxidation number of hydrogen in hydrides

Answer 11

-1

Question 12

Electrochemical series

Answer 12

K Ca Na Mg Al Zn Fe Sn Pb H Cu Ag Au

Question 13

5 Oxidising Agent

Answer 13

Acidified Potassium Manganate (VII)
Acidified Potassium Dichromate (VI)
Acidified Hydrogen Peroxide
Chlorine Water
Bromine Water

Question 14

1 Famous Reducing agent

Answer 14

Reactive metals

Question 15

Color of aqueous Chlorine

Answer 15

Pale Yellow

Question 16

Color of aqueous Bromine

Answer 16

Brown

Question 17

Color of aqueous Iodine

Answer 17

Brown

Question 18

Color of in Chlorine 1,1,1-trichloroethane layer

Answer 18

Colourless

Question 19

Color of in bromine 1,1,1-trichloroethane layer

Answer 19

brown

Question 20

Color of in iodine 1,1,1-trichloroethane layer

Answer 20

Purple

Question 21

Describe a chemical test to identify halogens

Answer 21

add 2cm3 of 1,1,1-trichloroethane to the test tube and shake gently.

Question 22

Definition of electrode potential

Answer 22

Potential difference produced when an equilibrium is established between metal M and the aqueous solution containing metal Mn+ ions in a half cell.

Question 23

Ion concentration at standard condition

Answer 23

1.0 mol dm-3

Question 24

Gas pressure at standard condition

Answer 24

1 atm / 101kPa

Question 25

temperature at standard condition

Answer 25

25c

Question 26

Non metal inert electrode at standard condition

Answer 26

Platinum

Question 27

Comparison between a larger and smaller standard electrode potential value

Answer 27

Element with larger E value is a stronger oxidising agent than with smaller E value Ion of Element with larger E value has a greater tendency to receive electron to form atom Ion of Element with larger E value undergoes reduction

Question 28

Definition of electrolytes

Answer 28

Substances that can conduct electricity in either molten state or aqueous solution and undergoes chemical changes

Question 29

Definition of Non-electrolytes

Answer 29

Substances that cannot conduct electricity in any state

Question 30

An example of Non-electrolytes

Answer 30

Covalent compounds

Question 31

2 examples of electrolytes

Answer 31

Ionic compounds in molten state Acid & Alkali in presence of water

Question 32

Particle that conduct electricity in an electrolyte

Answer 32

Ions

Question 33

Subatomic particles that conduct electricity in a conductor

Answer 33

Electrons

Question 34

Definition of electrolysis

Answer 34

A process whereby compounds in the molten state or aqueous solution decompose into their constituent elements by passing electricity trough them.

Question 35

Change of energy on electrolytic cells

Answer 35

Electrical energy -> chemical energy

Question 36

Change of energy in voltaic cells

Answer 36

Chemical energy -> electrical energy

Question 37

Flow of cation in an electrolytic cells when electric current is passed trough

Answer 37

To cathode

Question 38

Flow of antion in an electrolytic cells when electric current is passed trough

Answer 38

To Anode

Question 39

Effect of more negative or less positive E0 value on electrolysis at anode

Answer 39

Anions easier to release electrons and be oxidised

Question 40

Effect of less negative or more positive E0 value on electrolysis at cathode

Answer 40

Cations easier to receive electrons and be reduced

Question 41

Effect of higher halide ions concentration on electrolysis at anode

Answer 41

Halide ions easier to release electrons and be oxidised

Question 42

Effect of active electrodes on electrolysis at anode

Answer 42

No anions are discharged Metal atoms at the anode releases electrons to form metal ions

Question 43

Explain electroplating of metals through electrolysis

Answer 43

Electroplated object-cathode Electroplating metal-anode Electroplating metal ions-Electrolytes aqueous solution

Question 44

Extraction method for metals more reactive than carbon

Answer 44

Electrolysis

Question 45

Extraction method for metals less reactive than carbon

Answer 45

Reduction by carbon

Question 46

Extraction method for non reactive metals

Answer 46

No method. Exists as metal elements

Question 47

Explain extraction of Aluminium

Answer 47

Extracted through electrolysis Aluminium ore or Bauxite is purified into Aluminium oxide Aluminium Oxide is melted down with cryolite to lower its melting point Oxide ion oxidised at Anode Aluminium Ion reduced at Cathode

Question 48

Redox at Anode

Answer 48

Oxidation

Question 48

Redox at cathode

Answer 48

Reduction

Question 49

Explain extraction of Iron

Answer 49

Extracted through reduction by carbon Iron ore (hematite), limestone and coke is heated up in a blast furnace C + O2 -> CO2 C + CO2 -> 2CO Coke, C and Carbon Monoxide reduce Iron (iii) Oxide to Molten iron ( and produces carbon dioxide)

Question 50

Explain extraction using more reactive metal

Answer 50

When heated together, more reactive metal reduces less reactive metal from its metal oxide Metals are produced in molten state due to large amounts of heat released

Question 51

Definition of metal corrosion

Answer 51

Redox reaction when metal is oxidised spontaneuosly when metal atoms release electrons to form metal ions

Question 52

Relation between electropositivity of metal and tendency to corrode

Answer 52

More electropositive, more easier to corrode//rust