The Reactivity Series

Question 1

What factor puts metals in order on the reactivity series?

Answer 1

Water and dilute acid

Question 2

What happens if metals react with water or dilute acids?

Answer 2

Hydrogen gas given off

Gas “pops” with lighted spill

Question 3

How can metals be extracted from ores?

Answer 3

Metals in ores are chemically bonded to other elements
They have been oxidised
To extract metals from oxides
Metal oxide must be reduced

Question 4

What is the reaction like if a metal reacts with dilute acid?

Answer 4

Reactions are slow

Products of the reaction are a salt plus hydrogen gas

Question 5

Order of reativity

Answer 5

K Na Li = explode
K Na Li Ca = fizz off H2, leaves alkaline solution of metal hydroxide
Mg Al Zn Fe Ca = fizz off H2 forming salt
Mg Al Zn Fe = reactions slow
Sn Pb = slight reaction with steam, react slowly with warm acid
Cu Ag Au = no reaction

Question 6

Displacement

Answer 6

A more reactive metal will displace a less reactive metal from a compound
2Al + Fe2O3 → 2Fe + Al2O3

Aluminium is more reactive than iron
So iron is displaced (written by itself)

Iron is reduced
Aluminium is oxidised

Question 7

Oxidation and Reduction

Answer 7

OILRIG
Oxidation Is Loss (of electrons)
Reduction Is Gain (of electrons)

Question 8

Iron’s half equation for oxidation

Answer 8

Fe 2+ + 2e- → Fe

Question 9

On reactivity Series how are metals extracted

Answer 9

Potassium -> Aluminium = electrolysis
Carbon -> Copper = reduction
Platinum -> Silver = mined (form ores)

Question 10

How do you measure the worth of extracting a metal?

Answer 10

How easy it is to extract
How much metal is in the ore
Changing demands for a particular metal

(factors can change over time)

Question 11

Equation for salts from metals

Answer 11

metal + acid → a salt + hydrogen

Question 12

Process of obtaining salts from metals

Answer 12

Crystallisation

Question 13

Acid used provides negative ions present in all salts

Answer 13

Hydrochloric acid = chlorides
Sulfuric acid = sulphates
Nitric acid = nitrates

Question 14

Explaining the reaction between metal and an acid

Answer 14

Metal is put in acid
It gets smaller and smaller until it gets used up in the chemical reaction
Hydrogen gas (bubbles) are produced
This can be proven using a burning splint because hydrogen is flammable

Question 15

Redox

Answer 15

Involves a transfer of electrons between two species
An oxidation-reduction reaction is any chemical reaction in which the oxidation number of a molecule, atom, or ion changes by gaining or losing an electron.
Metal atoms → lose electrons → oxidised
Hydrogen ions from acid → gain electrons → reduced

Question 16

Salts from Insoluble Bases

Answer 16

Neutralisation: acid + base → a salt + water
Salts made up of positive metal ions and a negative ion from an acid
Alkalis are bases
They neutralise acids
Alkalises are soluble in water

Question 17

Making a Copper Salt

Answer 17

1) Add insoluble copper oxide to sulfuric acid and stir
2) Warm gently on tripod and gauze (don’t boil)
3) When solution is blue copper sulphate is being formed
4) Should be able to see excess black copper
5) Filter solution to remove excess copper oxide
6) Evaporate water so crystals form
7) Stop heating when see crystals first appear
8) Leave rest of water to evaporate slowly
9) Leave to dry in sun

Question 18

Acid and alkali equation

Answer 18

acid + alkali → a salt + water

Question 19

How is water formed from acid + alkali

Answer 19

ions react with OH- ions

Question 20

What is the reaction like with acid + alkali

Answer 20

No gas
No excess insoluble base visible
You need to use acid/base indicator to help decide when the reaction is complete

Question 21

Word equation with acids and carbonates

Answer 21

acid + a carbonate → a salt + water + carbon dioxide

Question 22

All acid equations

Answer 22

acid + metal →  salt + hydrogen
acid + metal oxide →  salt + water
acid + metal hydroxide →  salt + water
acid + metal base →  salt + water
acid + metal carbonate →  salt + water + carbon dioxide

Question 23

Neutralisation and pH scale

Answer 23

Alkali = soluble hydroxide produce OH- ions when added to water
Bases = substances that neutralise acids
Acids = substances that produce H+ ions when add to water
Pure water = neutral
Measure pH using universal indicator

Question 24

What are weak acids

Answer 24

Acids that don’t completely dissociate in solution

Carboxylic acids

Question 25

Strong acids

Answer 25

Completely dissociated or ionized in an aqueous solution

Hydrochloric acid

Question 26

pH and hydrogen ion concentration

Answer 26

Higher the concentration of H+ ions in an acidic solution, the lower the pH
Lower the concentration of H+ ions in an acidic solution, the higher the pH