Topic 4- Extracting Metals And Equilibra

Question 1

What is oxidation?

Answer 1

The Loss of electrons

Or the gain of oxygen

Question 2

What is reduction ?

Answer 2

The gain of electrons

The loss of oxygen

Question 3

What’s a good way to remember the difference between oxidation and reduction?

Answer 3

OIL RIG

oxidation is loss (of electrons)
Reduction is gain (of electrons)

Oxidation
Is
Loss
Reduction
Is
Gain

Question 4

What’s an example of oxidation?

Answer 4

E.g. when metals react with oxygen, metal oxides are produced:
Magnesium + oxygen → magnesium oxide
2Mg + O2 → 2MgO

Question 5

What’s an example of reduction ?

Answer 5

E.g. when metal oxides lose oxygen and return to their atomic form:
Iron oxide + carbon monoxide → iron + carbon dioxide
Fe2O3 + 3CO → 2Fe + 3CO2

Question 6

Sodium + oxygen —> ?

Answer 6

Sodium oxide

Question 7

Mg(s) + 2H+(aq) + 2Cl-(aq) → Mg2+(aq) + 2Cl-(aq) + H2(g)

In this ionic equation, what’s being oxidised and what’s being reduced?

Answer 7

Mg2+ is being oxidised

H+ is being reduced

Question 8

Mg(s) + 2H+(aq) + 2Cl-(aq) → Mg2+(aq) + 2Cl-(aq) + H2(g)

In this ionic equation, what is are the spectator ions ?

Answer 8

2Cl-(aq) ions

Question 9

When reacting with other substances, what ions do metal atoms always become ?

Answer 9

metal atoms always form positive ions.

Question 10

What is the reactivity of a metal linked to ?

Answer 10

how easy it is for a metal to form its positive ion

Question 11

What order can metals be arranged in ?

Answer 11

in order of their reactivity.

Question 12

What are examples of highly unreactive metals ?

Answer 12

Gold and platinum

Question 13

Where are gold and platinum found ?

And what do we call them ?

Answer 13

These metals are found in the Earth’s crust as pure metals. We call them native metals.

Question 14

Which non-metals are often included in the reactivity series of metals for reference?

Answer 14

Carbon

Hydrogen

Question 15

What is a displacement reaction ?

Answer 15

A more reactive metal (one that forms positive ions more easily) can remove a less reactive metal from a compound.

Question 16

When can a metal displace another metal from a compound ?

Answer 16

A metal can only displace another metal from a compound if it is located above it in the reactivity series.

Question 17

What’s an example of a displacement reaction ?

Calcium + copper sulfate → calcium sulfate + copper

Answer 17

Calcium is higher in the reactivity series than copper. This means that calcium is able to displace copper from a copper sulfate solution to create calcium sulfate.
Calcium + copper sulfate → calcium sulfate + copper
Ca(s) + CuSO4(aq) → CaSO4(aq) + Cu(s)
Platinum, on the other hand, is less reactive than copper and so would not be able to displace copper from a copper sulfate solution.

Question 18

What are redox reactions ?

Answer 18

Displacement reactions are examples of redox reactions.
In metal displacement reactions, the more reactive metal loses electrons (oxidised) and the less reactive metal gains electrons (reduced).

Question 19

What are the products of the reaction between magnesium and copper sulfate ?

Answer 19

Magnesium sulfate and copper

Question 20

What is the word and symbol equation for the displacement reaction :

Sodium bromide + chlorine → ? + ?
2NaBr + Cl2 → ? + ?

Answer 20

Sodium bromide + chlorine → sodium chloride + bromine.

2NaBr + Cl2 → 2NaCl + Br2

Question 21

What is the half equation for bromine ions in displacement reactions ?

Answer 21

Bromide ions are oxidised (electrons are lost):

2Br- → Br2 +2e-.

Question 22

What is the half equation for chlorine ions in displacement reactions ?

Answer 22

Chlorine is reduced (electrons are gained):

Cl2 + 2e- → 2Cl-.

Question 23

What are the spectator ions in the displacement reaction-

Sodium bromide + chlorine → sodium chloride + bromine.
2NaBr + Cl2 → 2NaCl + Br2

Answer 23

Sodium ions

Question 24

What are spectator ions ?

Answer 24

A spectator ion is an ion that doesn’t change during a chemical reaction.

Question 25

What is the reactivity series order ? Order From most reactive to least

Answer 25

``` Potassium Sodium Lithium Calcium Magnesium Aluminium CARBON - not a metal Zinc Iron HYDROGEN - not a metal Copper Silver Gold Platinum ```

Question 26

2NaBr(aq) + Cl2(g) → 2NaCl(aq) + Br2(l) | Which is the spectator ion in this equation?

Answer 26

Na +

Question 27

When Potassium, sodium and lithium all react quickly with cold water to produce what ?

Answer 27

a metal hydroxide and hydrogen gas

Question 28

What happens to potassium when reacted with cold water ?

Answer 28

Potassium is the most reactive so reacts very quickly. The hydrogen produced ignites instantly and the metal also sets alight, sparking and burning with a lilac flame

Question 29

What colour is the flame of potassium when it reacts with water ?

Answer 29

lilac flame

Question 30

What happens to sodium when reacted with cold water ?

Answer 30

Sodium fizzes rapidly and melts to form a ball that moves around on the water surface.

Question 31

What happens to lithium when reacted with cold water ?

Answer 31

Lithium fizzes steadily and floats, becoming smaller until it eventually disappears

Question 32

Most metals react with dilute acids to give what ?

Answer 32

a salt (e.g. copper chloride) and hydrogen gas

Question 33

What metals don’t react with dilute acids ?

Answer 33

copper, silver, gold and platinum.

Question 34

What metals react with dilute acids but not cold water ?

Answer 34

magnesium, aluminium, zinc, iron and lead (iron and lead react slowly). Metals don't have to be that reactive to react with dilute acids.

Question 35

Why is carbon used to extract metals?

Answer 35

Reducing a metal with carbon will result in the extraction of the metal if the metal is lower in the reactivity series than carbon. Carbon is used because it is cheap and abundant.

Question 36

How is carbon used to extract metals?

Answer 36

In the reduction, the metal oxide loses oxygen to form a pure metal. Reduction with carbon normally involves heating the metal oxide in the presence of the carbon, which is often used in the form of coal.

Question 37

What form is carbon often used in when reducing metal oxides?

Answer 37

Coal

Question 38

metal+acid→?+?

Answer 38

metal+acid→salt+hydrogen

Question 39

Fact about reactivity series’s

Answer 39

Potassium down to aluminium are more reactive than carbon and so cannot be extracted by reduction with carbon. Silver, gold and platinum are either found as natural elements or can be simply extracted by heating directly in air. The remaining metals - zinc, iron, and copper - are all commonly extracted by reduction with carbon.

Question 40

What type of reaction is used when extracting metals using carbon ?

Answer 40

Reduction