4. Chemical Changes

Question 1

What is produced when a metal reacts with oxygen?

Answer 1

metal + oxygen -> metal oxide

Question 2

What is oxidation?

Answer 2

Gain of oxygen; loss of electrons

Question 3

What happens to reactivity in terms of electrons?

Answer 3

The more easy it is to lose electrons, the more reactive the metal is

Question 4

Mnemonic for the reactivity series?

Answer 4

Please send Charlie monkeys and cute zebras in tall long hard cages most securely guarded please

Question 5

What is reduction?

Answer 5

Loss of oxygen & gain of electrons

Question 6

What are the products of metal + acid?

Answer 6

Salt and hydrogen

Question 7

What is OILRIG?

Answer 7

oxidation is loss, reduction is gain

Question 8

What can metals more reactive than carbon be extracted using?

Answer 8

Electrolysis

Question 9

What can metals less reactive than carbon be extracted using?

Answer 9

Reduction using carbon, coke or charcoal

Question 10

What can elements less reactive than hydrogen be extracted using?

Answer 10

They don’t need extracting - they can occur native

Question 11

What is displacement?

Answer 11

When a more reactive element takes the place of a less reactive element

Question 12

How do you work out the relative atomic mass?

Answer 12

Multiply each mass number of each isotope by its % abundance

Add together

Divide by 100

Question 13

What are bases?

Answer 13

Substances that react with acids and neutralise them (form a salt and water and sometimes carbon dioxide)

Question 14

What is a base that is soluble in water also called?

Answer 14

An alkali

Question 15

Are most bases insoluble?

Answer 15

Yes

Question 16

What are acids?

Answer 16

Substances that react with water to release H+ ions

Question 17

What are alkalis?

Answer 17

Bases that are soluble in water and react with water to release OH- ions

Question 18

What some common acids?

Answer 18

Hydrochloric acid, sulphuric acid, nitric acid

Question 19

What does acid + metal oxide give?

Answer 19

Acid + metal oxide -> salt + water

Question 20

What does acid + metal hydroxide give?

Answer 20

Acid + metal hydroxide -> salt + water

Question 21

What does acid + metal carbonate give?

Answer 21

Acid + metal carbonate -> salt + water + carbon dioxide

Question 22

What does acid + ammonia give?

Answer 22

Acid + ammonia -> ammonium salt

Question 23

What do acids react with water to give?

Answer 23

H+ ions

Question 24

What do bases form when reacting with acids?

Answer 24

Salt and water (and sometimes carbon dioxide)

Question 25

What do alkalis release when they react with water?

Answer 25

OH- ions

Question 26

What are salts?

Answer 26

Ionic substances formed when acids react with bases

Question 27

Does copper react with acid?

Answer 27

No

Question 28

What is electrolysis?

Answer 28

The process where an ionic substance that is molten or dissolved is broken into elements using electricity

Question 29

What does PANIC stand for?

Answer 29

Positive is anode. Negative is cathode

Question 30

What charge is the anode?

Answer 30

Positive

Question 31

What charge is the cathode?

Answer 31

Negative

Question 32

What charge are anions?

Answer 32

Negative

Question 33

What charge are cations?

Answer 33

Positive

Question 34

What bonds do elements form at the anode?

Answer 34

Covalent

Question 35

How do elements leave the system at the anode?

Answer 35

As gaseous diatomic molecules

Question 36

What elements do bonds form at the cathode?

Answer 36

Metallic bonds with each other

Question 37

What happens in terms of electrons at the cathode?

Answer 37

Each positive ion accepts electrons until it is charged

Question 38

What happens to lost electrons at the anode?

Answer 38

They flow around the circuit to the negative electrode

Question 39

Why do substances have to be in a solution or liquid during electrolysis?

Answer 39

So ions are free to move

Question 40

What side of the equation do electrons appear on in oxidation?

Answer 40

The right hand side

Question 41

What side of the equation do electrons appear on in reduction

Answer 41

Left hand side

Question 42

Aluminium oxide -> aluminium + oxygen Which are the cations and which are the anions?

Answer 42

Aluminium ions are cations and oxygen ions are anions

Question 43

What are electrodes made from?

Answer 43

Graphite

Question 44

What is used to dissolve aluminium oxide ore?

Answer 44

molten cryolite

Question 45

Why does the anode need to be replaced regularly?

Answer 45

It heats up and then reacts so breaks down - CO2 will start to be produced

Question 46

What happens to remains of disintegrated anodes?

Answer 46

Dismantled and new ones made out of them

Question 47

What does discharges mean?

Answer 47

Lost charge

Question 48

Which positive ions are discharged in a solution?

Answer 48

Ions lower than hydrogen in the reactivity series

Question 49

What is formed when H+ ions are discharged in electrolysis?

Answer 49

H2

Question 50

Which negative ions are discharged in a solution?

Answer 50

If the compound contains halide ions they are discharged. If not it's OH-

Question 51

What is formed when OH- ions are discharged during electrolysis?

Answer 51

O2