C2.2 Ionic compounds and analysis

Question 1

What is an ion?

Answer 1

An atom with a positive or negative charge

Question 2

How do atoms become ions?

Answer 2

They lose or gain electrons in chemical reactions

Question 3

What are cations?

Answer 3

Positively charged ions

Question 4

How do atoms become cations?

Answer 4

They lose electrons

Question 5

What are anions?

Answer 5

Negatively charged ions

Question 6

How do atoms become anions?

Answer 6

They gain electrons

Question 7

Is a metal ion a cation or an anion?

Answer 7

Cation

Question 8

Is a non-metal ion a cation or an anion?

Answer 8

Anion

Question 9

Why do anions gain electrons?

Answer 9

To complete their outer shells

Question 10

Do oppositely charged ions attract or repel?

Answer 10

Attract

Question 11

What are ionic bonds?

Answer 11

Strong electrostatic forces between oppositely charged atoms

Question 12

What is the charge of an ionic compound?

Answer 12

0, neutral

Question 13

Why is an ionic compound neutral?

Answer 13

There are equal numbers of positive and negative charges

Question 14

What are compound ions?

Answer 14

Ions that contain more than one element

Question 15

What is a lattice structure?

Answer 15

When something is arranged in a regular way

Question 16

When can ionic substances conduct electricity?

Answer 16

When they are molten or in aqueous solution

Question 17

What two conditions must be met for a substance to conduct electricity?

Answer 17

It must contain charged particles and those particles must be free to move

Question 18

Why can’t ions conduct electricity when they’re solid?

Answer 18

The ions are held in fixed positions because they’re in a lattice structure so they can only vibrate

Question 19

What is the melting point?

Answer 19

The temperature at which a substance turns from a solid to a liquid

Question 20

What is the boiling point?

Answer 20

The temperature at which a substance turns from a liquid to a gas at its fastest possible rate

Question 21

Do ionic substances have high or low melting and boiling points?

Answer 21

High

Question 22

Why do ionic compounds have high melting and boiling points?

Answer 22

Ionic bonds are very strong so a lot of energy is needed to break them

Question 23

What does soluble mean?

Answer 23

A substance that dissolves well in a liquid

Question 24

What does insoluble mean?

Answer 24

A substance that doesn’t dissolve in a liquid at all

Question 25

What is a salt?

Answer 25

A substance that can be made by reacting an acid and an alkali

Question 26

What is a precipitate?

Answer 26

An insoluble product of a reaction

Question 27

What is a precipitation reaction?

Answer 27

A reaction in which an insoluble solid is produced from two soluble substances

Question 28

How can you separate the precipitate from unreacted ions?

Answer 28

- through filtration - then washing it on the filter paper - then drying it in a warm oven

Question 29

Are chlorides, nitrates and common potassium salts soluble or insoluble?

Answer 29

Soluble

Question 30

Are hydroxides and lead salts soluble or insoluble?

Answer 30

Insoluble

Question 31

What is a barium meal?

Answer 31

A drink containing barium sulphate used for X-rays

Question 32

Why is barium sulphate used in X-rays?

Answer 32

It shows up opaque on X-rays because X-rays don't pass through but get absorbed

Question 33

Why is barium sulphate safe to swallow while most barium salts are toxic?

Answer 33

Barium sulphate is insoluble which means it doesn't get absorbed into the blood

Question 34

Why are flame tests used?

Answer 34

To help identify elements

Question 35

What colour does sodium go during a flame test?

Answer 35

Yellow

Question 36

What colour does potassium go during a flame test?

Answer 36

Lilac

Question 37

What colour does calcium go during a flame test?

Answer 37

Red

Question 38

What colour does copper(||) go during a flame test?

Answer 38

Green-blue

Question 39

What is a spectroscopy?

Answer 39

The analysis of light on a spectrum using flame tests

Question 40

How do you do a spectroscopy?

Answer 40

You study the light given off flame tests on mineral water. Then a prism is used to separate the colours

Question 41

How were caesium and rubidium discovered?

Answer 41

Using a spectroscopy

Question 42

How do you identify aqueous chloride ions?

Answer 42

- you add a few drops of dilute nitric acid to the sample solution which is shaken - you then add a few drops of silver nitrate solution - if a white precipitate of silver chloride forms there are chloride ions

Question 43

How do you identify aqueous sulphate ions?

Answer 43

- you add a few drops of dilute hydrochloric acid to the sample solution which is shaken - you then add a few drops of barium chloride solution - if a white solution of barium sulphate forms the solution contains sulphate ions

Question 44

How do you test for carbonate ions?

Answer 44

- you add acid to the substance so that gas is given off | - if the gas turns limewater milky then it is carbon dioxide