Chemistry A1 (complete)

Question 1

Acid

Answer 1

a substance that dissociates in water to form positive hydrogen ions

Question 2

Base

Answer 2

a substance that will react with acids to form salt and water

Question 3

Alkali

Answer 3

a base that dissolves in water to form negative hydroxide ions

Question 4

Amphoteric

Answer 4

substances that can act as both an acid and a base

Question 5

Why is Aluminium useful

Answer 5

it is chemically inert (unreactive) except in hot acids/bases and amphoteric

Question 6

uses of Aluminium

Answer 6

drying agent
paint
sun cream
filer
glass

Question 7

Salt

Answer 7

formed when the cation in an acid is replaced by a different cation often a metal or ammonium

Question 8

Metal oxides

Answer 8

bases

Question 9

Metal hydroxides

Answer 9

Alkalis

Question 10

electrolysis

Answer 10

the decomposition of a compound using electricity

Question 11

effluent

Answer 11

liquid waste usually discharged into a river or stream

Question 12

acid + metal hydroxide =

Answer 12

salt + water

Question 13

Activation energy

Answer 13

minimum amount of energy needed between colliding particles in order for a successful collisions to take place

Question 14

contact process

Answer 14

industrial production of sulfuric acid

Question 15

steps of the contact process

Answer 15

1. sulfur is burnt in oxygen to produce sulphur dioxide (S + O2 -> SO2)
2. sulphur dioxide takes part in a reverse reaction with more oxygen to make sulphur trioxide. Vanadium oxide is added as the catalyst for sulfur dioxide to react with forming V2O4. it then regrates to V2O5
3. a small amount of sulfuric acid is used with the sulfuric trioxide to make fuming sulfuric acid
4. water is added to produce sulfuric acid

Question 16

Iron in the harbour process

Answer 16

provides a surface area for hydrogen and nitrogen to absorb/bind to. this weakens the reactants allowing the chemical reaction to take place more easily therefore lowering the reaction activity.

Question 17

discribe titaniums ore

Answer 17

titaniums ore is called rutile and consists of itanium oxide

Question 18

why cant carbon be used as reducing agent in the production of pure titanium

Answer 18

because it would make the titanium britle

Question 19

what is used as a reducing agent in the production of titanium

Answer 19

magnisium

Question 20

why is pure titanium expensive

Answer 20

because only a small amout is made at one time

Question 21

what is a batch process

Answer 21

a process that takes place in two stages

Question 22

steps of the Kroll process

Answer 22

Stage one: titanium oxide is converted into titanium chloride using chlorine and carbon
Stage two: titanium chloride is reduced using magnisium

Question 23

what envirement is the redcution of titanium carried out in

Answer 23

it is carried out in an argon atmosphere to prevent the titanium reacting with water or oxygen

Question 24

what is brine

Answer 24

aqueous sodium chloride

Question 25

what is produced from brine electrolysis and what is it used for

Answer 25

• chlorine gas which can be used in cleaning products
• hydrogen gas which can be used as feul
• sodium hydroxide solution which can be used in bleach and other cleaning products

Question 26

what are the two cell types that can be used in the electrolysis of brine

Answer 26

diaphram and membrane

Question 27

what is product at the anode

the electrolysis of brine

Answer 27

chlorine gas
2Cl- 🡢 Cl^2 +2e-

Question 28

What is produced at the cathode

the electrolysis of brine

Answer 28

hydrogen gas
2H+ + 2e- 🡢 H^2

Question 29

explain the key fetures of the diaphagm cell model

the electrolysis of brine

Answer 29

• brine is pumped in on a higher level to ensure the flow is from left to right and to prevent the back flow of sodium hydroxide
• some brine will be left over in the sodium hydroxide produced

Question 30

explain the key fetures of the membrane cell

the electrolysis of brine

Answer 30

• it only allows the movement of postive ions across the ion exchange membrane, this means brine does not cross it. This results in purer sodium hydroxide

Question 31

Bauxite

Answer 31

Aluminium ore

Question 32

Slurry

Answer 32

semi-liquid material containing fine soild particals

Question 33

Flocculants

Answer 33

substances that cause particles to clump together

Question 34

Calcination

Answer 34

using heat to remove water

Question 35

the steps of extracting alumina from bauxite

Answer 35

1. large pieces of bauxite are crushed up into small grains
2. hot sodium hydroxide is added to the small grains to dissolve the aluminium minerals. this is known as digestion and produces slurry
3. the slurry us taken and filtered to remove large residue leaving alminium compound
4. the alminium comound is left to cool, forming crystals. flocculants are added to aid the sedimentation process. the sodium hydroxide is recovered and reused
5. calcination is carried out on the crystals leaving alumina

Question 36

the steps to create aluminium from alumina

Answer 36

1. alumina is dissolved in cryolite
2. electolysis is used to produce molton aluminum

Question 37

what is used as the electrolyte in the elctrolysis of alumina

Answer 37

molten cryolite is used because it melts at -1000 and the alumina easly dissolves in it.

To further reduce the melting point aluminium fluoride it added.

Question 38

What happens to the water present in the electrolysis of brine

Answer 38

The water molecules dissociate

Question 39

why is aluminium usefull and what is it used for

Answer 39

aluminium is versatile, its lightweight, unreactive and flexable making it uses full for many things.
* cans, foils, kitchen utensils, window frames, beer kegs and aeroplane parts

Question 40

Properties of titanium

Answer 40

Reactive
Non-corrosive
High strength to weight ratio

Question 41

Uses of titanium

Answer 41

Aerospace- air craft engines
Golf cubs