Paper 2- Inorganic Chemistry

Question 1

Explain the process of titration in detail. (using hydrochloric acid and sodium hydroxide as an example)

Answer 1

• Using pipette & pipette filler add some alkali (about 25cm3) to conical flask with 2/3 drops of indicator
• Fill a burette with acid & do this below eye level
• Using burette add acid to alkali a bit at a time & give conical flask a regular swirl
• Indicator changes colour when all alkali has been neutralised (e.g phenolphthalein = pink in alkalis but colourless in acids)
• record volume of acid used to neutralise alkali
• repeat process for reliable results

Question 2

Titration calculation formula

Answer 2

mol

vol x conc

Question 3

Give the steps taken in a titration calculation when you need to find the concentration of an acid

Answer 3

1) work out the moles of the known substance

Question 4

Name the elements in the reactivity series

Answer 4

Potassium 
Sodium 
Lithium
Calcium
Magnesium
Aluminium
Zinc
Iron
Copper
Silver
Gold

Question 5

Name the 4 most reactive elements in the reactivity series

Answer 5

Potassium
Sodium
Lithium
Calcium

Question 6

Name the 3 fairly reactive elements in the reactivity series

Answer 6

Magnesium
Aluminium
Zinc

Question 7

Name the 3 not very reactive elements in the reactivity series

Answer 7

Iron
Copper
Silver

Question 8

Name the not reactive element in the reactivity series

Answer 8

Gold

Question 9

How does metals reacting with dilute acids tell you how reactive they are

Answer 9

-the more reactive the metal the faster the reaction will go

Question 10

acid + metal –>

Answer 10

salt + hydrogen

Question 11

Describe the steps you would take in the practical to investigate the differences in reactivity of a variety of metals by using their reaction with acids

Answer 11

1) set up 3 boiling tubes and fill with equal volumes of dilute hydrochloric acid/ dilute sulfuric acid
2) place pieces of magnesium, zinc, iron in separate test tubes
- speed of reaction is indicated by the rate of hydrogen bubbles given off
- hydrogen is confirmed by burning splint test

Question 12

give the word equation for metals reacting with water

Answer 12

metal + water –>

metal hydroxide + hydrogen

Question 13

how do very reactive metals react with water

Answer 13

• react vigorously with water:

- produce bubbles of hydrogen gas

Question 14

how do less reactive metals react with water

Answer 14

-won’t react much with cold water

Question 15

why do more reactive metals displace less reactive metals

Answer 15

• as more reactive metals react more strongly than less reactive metals
• meaning more reactive metals displace a less reactive metal from its oxide as it will bond more strongly to the oxygen

Question 16

iron oxide + aluminium –>

-which element is being displaced in this reaction

Answer 16

aluminium oxide + iron

-iron would be displaced from iron oxide by the more reactive aluminium

Question 17

what occurs if you put a reactive metal into a solution of a less reactive metal

Answer 17

-reactive metal replaces the less reactive metal in the salt

Question 18

copper sulfate + iron –>

Answer 18

iron sulfate + copper

Question 19

what happens if a piece of silver metal is put into copper sulfate solution

Answer 19

-nothing happens as the more reactive metal (copper) is already in the salt

Question 20

What conditions are needed for iron to rust?

Answer 20

Oxygen and Water

Question 21

What is the name of the chemical reaction that occurs when iron rusts

Answer 21

-oxidation reaction

Question 22

What is the chemical name of rust?

Answer 22

Hydrated iron(III) oxide

Question 23

How can barrier methods prevent rust

Answer 23

-barrier methods coat the iron with a barrier keeping out the water and oxygen

Question 24

Name some barrier method to prevent rust

Answer 24

• paint
• oil
• grease

Question 25

Name another way of preventing iron rusting other than barrier methods

-what does this method involve

Answer 25

• sacrificial method
• involved placing a more reactive metal (zinc) with the iron.
• The water and oxygen then react with the sacrifical metal instead of iron

Question 26

Rusting can be prevented by spraying iron in zinc, this is called …

Answer 26

Galvanising

Question 27

Meaning of Oxidation

Answer 27

• Gain of oxygen

- Lose of electrons

Question 28

Meaning of Reduction

Answer 28

• Loss of oxygen

- Gain of electrons

Question 29

Meaning of Redox reactions

Answer 29

Reduction and Oxidation reactions.

Question 30

Oxidising agent

Answer 30

-substance that oxidises the metal

-and gets reduced:
Gains electrons
Loses oxygen

Question 31

Reducing agent

Answer 31

-substance that reduces metal

• and gets oxidised
• Loses electrons
• Gains oxygen

Question 32

magnesium + oxygen –> magnesium oxide

-what is being oxidised in this freaction

Answer 32

-magnesium is oxidised to magnesium oxide