Extracting metals and equilibria

Question 1

What do the most reactive metals react with

Answer 1

Water

Question 2

What is the equation for a metal + water

Answer 2

Metal + Water » metal hydroxide + hydrogen

Question 3

What do fairly reactive metals react with

Answer 3

Acids

Question 4

What is the equation of metal + acid

Answer 4

Metal + acid » salt + hydrogen

Question 5

What do all metals react with

Answer 5

Oxygen

Question 6

What is the equation for metal + oxygen

Answer 6

Metal + oxygen » metal oxide

Question 7

What is the only metal that doesn’t react with water, acid or oxygen

Answer 7

gold

Question 8

What are displacement reactions

Answer 8

When a more reactive metal displaces the less reactive metal causing it to be left uncombined

Question 9

Explain the displacement reactions as redox reactions

Answer 9

• More reactive metals form a cation losing electrons and being oxidised
• Less reactive metals from anions gaining electrons when displaced being reduced

Question 10

What is reactivity

Answer 10

The tendency of the metal atom to form cations

Question 11

What are the three elements that react with water

Answer 11

Potassium
Sodium
Calcium

Question 12

What elements react with dilute acid

Answer 12

Magnesium, Aluminium, Zinc, Iron

Question 13

What elements are least reactive

Answer 13

Copper, Silver, Gold

Question 14

Where are most metals found

Answer 14

In the earth’s crust
-Most metals found as ores
-Unreactive metals found uncombined

Question 15

What is oxidation (when relating to oxygen)

Answer 15

The gain of oxygen

Question 16

What is reduction (In terms of oxygen)

Answer 16

The loss of oxygen

Question 17

How can a metal be extracted from it’s ore chemically

Answer 17

By reduction using carbon
metal oxide + carbon → metal + carbon dioxide
When an ore is reduced, oxygen is removed from it

Question 18

What are ores

Answer 18

a rock that contains metals or metal compounds in a high enough concentration

Question 19

How do you extract a metal from its ore if the metal is less reactive than carbon

Answer 19

Reduction of carbon

Question 20

How do you extract a metal from its ore if the metal is MORE reactive than carbon

Answer 20

Electroysis

Question 21

What is phytoextraction

Answer 21

• When plants absorb metal compounds through they’re roots
• Ions are concentrated through shoots and leaves
• Plants are harvested and burnt and the ash contains a higher concentration of metal than the ore

Question 22

What is bioleaching

Answer 22

• Some bacteria absorb metal compounds
• Produce leachates which contain them
• Scrap iron or electrolysis can be used to obtain the metal

Question 23

Explain how a metals relative resistance to oxidation is related to its position in the reactivity series

Answer 23

• the less reactive the metal is, the greater its resistance to oxidation
• the more reactive the metal, the greater the tendency to form cations

Question 24

What are the advantages of recycling metals

Answer 24

• requires less energy than extracting them, so saves money
• Mining ores is bad for the environment as large quarries are created,

Question 25

Why is extracting raw materials bad for the earth

Answer 25

requires lots of energy which comes from fossil fuels, which are non-renewable and the process contributes to acid rain and climate change

Question 26

What are the stages analysed in a life cycle assessment

Answer 26

1. making materials for the product from the raw materials needed
2. manufacturing the product
3. transport of the product (and raw materials)
4. using the product
5. disposing of the product at the end of its useful life

Question 27

What are reversible reactions

Answer 27

Reactions were the products of the reaction can react to produce the original reactants

Question 28

What are Chatelier’s three ways of adjusting equilibrium

Answer 28

Changing the conditions
* temperature
* pressure
* concentration

Question 29

What is equilibrium

Answer 29

Rate of forward reaction = rate of backward reaction

Question 30

What is dynamic equilibrium

Answer 30

When the front and back reaction reach equilibrium they keep going

Question 31

What is the word equation for the formation of the Haber process

Answer 31

nitrogen + hydrogen ⇌ ammonia

Question 32

What is the symbol formula for the Haber process

Answer 32

N 2 (g) + 3H 2 (g) ⇌ 2NH 3 (g)

Question 33

What are the conditions needed for the Haber process

Answer 33

Temperature: 450°C
Pressure: 200atm
An iron catalyst

Question 34

Where is nitrogen obtained

Answer 34

From the air

Question 35

Where is hydrogen obtained from

Answer 35

Natural gas

Question 36

How is the position of a dynamic equilibrium affected by temperature

Answer 36

When temperature is increased: Equilibrium moves to the direction of the endothermic reaction
If decreased:
Equilibrium moves to the direction of exothermic reaction

Question 37

How is the position of a dynamic equilibrium affected by changing concentration

Answer 37

Increased: Position of equilibrium shifts towards products so more reactants are produced
Decreased: Position of equilibrium shifts towards reactants so more produvts are produced

Question 38

How is the position of a dynamic equilibrium affected by pressure

Answer 38

Decrease: Equilibrium will favour the side with more particles
Increase: Equilibrium will favour the side with less particles

Question 39

What is Le Chatelier’s theory

Answer 39

if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium shifts to counteract the change