Extracting Metals and Equilibrium

Question 1

What are the products when a metal reacts with cold water?

Answer 1

Metal hydroxide and hydrogen gas

Question 2

What are the products when a metal reacts with steam?

Answer 2

Metal oxide and hydrogen gas

Question 3

What are the products when a metal reacts with a dilute acid?

Answer 3

Salt and hydrogen

Question 4

If a metal reacts with cold water, what does it suggest above the reactivity of this metal?

Answer 4

The metal is very reactive as only the most reactive can react with cold water

Question 5

What does a metal reacts with oxygen but not acid or cold water suggest about the reactivity of this metal?

Answer 5

Not very reactive, most metals react with oxygen

Question 6

What metal won’t react with water, acid or oxygen?

Answer 6

Gold

Question 7

What is an experiment that uses displacement to compare the reactivity of two metals?

Answer 7

Add a solid metal to a salt solution, if the solid metal is more reactive, it will gradually disappear, displacing the metal that was in the salt solution and if nothing happens, the metal in the salt is more reactive and can’t be displaced

Question 8

What would you expect to observe when magnesium is added to copper sulfate solution?

Answer 8

The copper sulfate solution is blue, magnesium is more reactive than copper so when magnesium is added the blue solution decolourises and copper coats the surface of the magnesium

Question 9

Why can a displacement reaction be called a redox reaction?

Answer 9

Occurs when reeducation and oxidation are taking place, in a displacement reaction the more reactive metal atoms lose electrons to form ions and the lies reactive metal ions gain electrons to form the elements

Question 10

Which metals are most easily oxidised?

Answer 10

Highest in the reactivity series, more likely to react with water and dilute acids to form cations

Question 11

Where are most metals extracted from?

Answer 11

From ores found in the Earths crust

Question 12

What is an ore?

Answer 12

A rock which contains metals often chemically combined with other substances

Question 13

Which metals are found in the earths crust as uncombined elements?

Answer 13

Unreactive metals

Question 14

What does oxidation mean?

Answer 14

Gain of oxygen

Question 15

What does reduction mean?

Answer 15

Loss of oxygen

Question 16

How can metals be extracted from their ores?

Answer 16

Reeducation with carbon: can only be done if the metal is less reactive than carbon and Electrolysis: can be done with all metals, but requires a large amount of energy

Question 17

How would you extract iron from its ore?

Answer 17

Iron is less reactive than carbon so can be extracted by reduction with carbon and electrolysis could also be used but this would use a lot of unnecessary energy

Question 18

How can aluminium be extracted from its ore?

Answer 18

Aluminium is more reactive than carbon so electrolysis must be used and when the molten ore undergoes electrolysis the metal forms at the cathode

Question 19

When aluminium is extracted from aluminium oxide, why is it first dissolved in molten cryolite?

Answer 19

Aluminium oxide has a very high melting point, it’s dissolved in molten cryolite to produce an electrolyte with a lower melting point, reducing energy usage and cost

Question 20

How can plants be used as an alternative metal extraction method? How does it work?

Answer 20

Phytoextraction: plants are grown in areas with metals in the soil, the plants take up metals through their roots and concentrate them in their shoots and leaves, these plants are burned and the metals are removed from the ash

Question 21

How can bacteria be used as an alternative metal extraction method?

Answer 21

Bacteria extraction: some bacteria absorb metal compounds, these bacteria produce solution called leachates containing the metals and scrap iron can be used to remove the metal from the leachate

Question 22

What are limitations of biological methods of extraction?

Answer 22

Only suitable for low grade ores with smaller quantities of metals, slow processes and require displacement or electrolysis for the final step

Question 23

How is a metals relative resistance to oxidation related to its position in the reactivity series?

Answer 23

Metals lower in the reactivity series are less reactive, this means they are less likely to form their cations so are more resistant to oxidation

Question 24

What are the advantages of recycling metals?

Answer 24

Economically beneficial, less wage produced so less landfill, less energy is required, more sustainable and recycling process provides employment

Question 25

What is a life cycle assessment?

Answer 25

Analysis of the overall environmental impact that a product may have throughout its lifetime

Question 26

What different factor does a life cycle assessment of a product consider?

Answer 26

Extraction and processing of raw materials, manufacturing, packaging and transportation, use of the product and disposal

Question 27

What is a reversible reaction?

Answer 27

A reaction in which the products can react to torn the original reactants

Question 28

How can the direction of a reversible reaction be altered?

Answer 28

Changing the reaction conditions

Question 29

What is meant by the term dynamic equilibrium?

Answer 29

The rate of the forward reaction equals the rate of the backwards reaction, this means the concentration of reactants and products are constant even though compounds are continually reacting

Question 30

What is a closed system?

Answer 30

A system where nothing is added or removed, all reactants and products remain in the reaction vessel

Question 31

Why is equilibrium only reached if the reaction takes place in a closed system?

Answer 31

The closed system prevents any reactants and products escaping so that they are able to react continuously

Question 32

What is the Hager process?

Answer 32

An industrial process used to produce ammonia

Question 33

Where are the sources of nitrogen and hydrogen for the Huber process?

Answer 33

Nitrogen: extracted from the air and Hydrogen: obtained from natural gas

Question 34

What conditions are used for the Habor process?

Answer 34

450C temperature, 200 atm pressure and iron catalysts

Question 35

What is the effect of increasing the temperature of a reversible reaction if the forward reaction is endothermic?

Answer 35

The towards reaction is endothermic so increasing the temperature favours the forwards reaction, the equilibrium will shift towards the forward reaction and the yield of the product

Question 36

What is the effect of changing the pressure of a reversible gaseous reaction?

Answer 36

An increase in pressure will favour the reaction that produces the least number of molecules, the equilibrium positions will shift towards the side that produces the fewest gaseous molecules

Question 37

What is the effect of increasing the pressure in the yield of ammonia in the Haber produces?

Answer 37

Increasing the pressure will shift equilibrium to the right as there are fewer molecules of gas, the yield of ammonia will increase

Question 38

What effect does the concentration of the reactants are increased during a reversible reaction on the equilibrium position?

Answer 38

The equilibrium will shift to the right so the product yield will increase, this will reduce the effect of the increased concentration of the reactants