Extracting metals and equilibria Flashcards
What do the most reactive metals react with
Water
What is the equation for a metal + water
Metal + Water » metal hydroxide + hydrogen
What do fairly reactive metals react with
Acids
What is the equation of metal + acid
Metal + acid » salt + hydrogen
What do all metals react with
Oxygen
What is the equation for metal + oxygen
Metal + oxygen » metal oxide
What is the only metal that doesn’t react with water, acid or oxygen
gold
What are displacement reactions
When a more reactive metal displaces the less reactive metal causing it to be left uncombined
Explain the displacement reactions as redox reactions
- More reactive metals form a cation losing electrons and being oxidised
- Less reactive metals from anions gaining electrons when displaced being reduced
What is reactivity
The tendency of the metal atom to form cations
What are the three elements that react with water
Potassium
Sodium
Calcium
What elements react with dilute acid
Magnesium, Aluminium, Zinc, Iron
What elements are least reactive
Copper, Silver, Gold
Where are most metals found
In the earth’s crust
-Most metals found as ores
-Unreactive metals found uncombined
What is oxidation (when relating to oxygen)
The gain of oxygen
What is reduction (In terms of oxygen)
The loss of oxygen
How can a metal be extracted from it’s ore chemically
By reduction using carbon
metal oxide + carbon → metal + carbon dioxide
When an ore is reduced, oxygen is removed from it
What are ores
a rock that contains metals or metal compounds in a high enough concentration
How do you extract a metal from its ore if the metal is less reactive than carbon
Reduction of carbon
How do you extract a metal from its ore if the metal is MORE reactive than carbon
Electroysis
What is phytoextraction
- 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
What is bioleaching
- Some bacteria absorb metal compounds
- Produce leachates which contain them
- Scrap iron or electrolysis can be used to obtain the metal
Explain how a metals relative resistance to oxidation is related to its position in the reactivity series
- the less reactive the metal is, the greater its resistance to oxidation
- the more reactive the metal, the greater the tendency to form cations
What are the advantages of recycling metals
- requires less energy than extracting them, so saves money
- Mining ores is bad for the environment as large quarries are created,
Why is extracting raw materials bad for the earth
requires lots of energy which comes from fossil fuels, which are non-renewable and the process contributes to acid rain and climate change
What are the stages analysed in a life cycle assessment
- making materials for the product from the raw materials needed
- manufacturing the product
- transport of the product (and raw materials)
- using the product
- disposing of the product at the end of its useful life
What are reversible reactions
Reactions were the products of the reaction can react to produce the original reactants
What are Chatelier’s three ways of adjusting equilibrium
Changing the conditions
* temperature
* pressure
* concentration
What is equilibrium
Rate of forward reaction = rate of backward reaction
What is dynamic equilibrium
When the front and back reaction reach equilibrium they keep going
What is the word equation for the formation of the Haber process
nitrogen + hydrogen ⇌ ammonia
What is the symbol formula for the Haber process
N 2 (g) + 3H 2 (g) ⇌ 2NH 3 (g)
What are the conditions needed for the Haber process
Temperature: 450°C
Pressure: 200atm
An iron catalyst
Where is nitrogen obtained
From the air
Where is hydrogen obtained from
Natural gas
How is the position of a dynamic equilibrium affected by temperature
When temperature is increased: Equilibrium moves to the direction of the endothermic reaction
If decreased:
Equilibrium moves to the direction of exothermic reaction
How is the position of a dynamic equilibrium affected by changing concentration
Increased: Position of equilibrium shifts towards products so more reactants are produced
Decreased: Position of equilibrium shifts towards reactants so more produvts are produced
How is the position of a dynamic equilibrium affected by pressure
Decrease: Equilibrium will favour the side with more particles
Increase: Equilibrium will favour the side with less particles
What is Le Chatelier’s theory
if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium shifts to counteract the change
