Topic 4 - Extracting Metals and Equilibria Flashcards
Metals reactivity can be determined by their reactions with
Acids, water, salt solution
A metal is more reactive if
It loses its outer elctrons easier
Metals reaction with acids
They fizz, and the more reactive metals fizz more vigorously and the reaction goes faster. Hydrogen is the gas formed. The amount of hydrogen can be tested usign the burning splint test, so the loudy the squeaky pop the more hydrogen.
Metals reaction with water
Metal+water –> metal hydroxide + hydrogen
Meatls that react vigorously with water
Very reactive metals like potassium, sodium, lithium and calcium
Meatls that dont react with water but react with steam
Less reactive metals like magnesium, zinc and iron
Metal that doesnt react with water or steam
Copper, silver, gold
Determining the reactvity of metals using slat solutions is called
Displacement reactions
Dispalcement reactiosn are
Redox reactions because both oxidation and reduction happen
Oxidation is
The loss of electrons and the gain fo oxygen
Reduction is
The gain in electrons and the loss of oxygen
In dispalcement reactions, a metal is reacted with
A metal salt solution
What occurs duirng displacement reactions
If the metal is more reactive than the metal in solution, it replaces it. If not then nothing happens
In displacement reactions which metal loses and gains electrons
The less reactive metal gaisn electrons(reduction) and the more reactive metal loses elctrons(oxidation)
The reactivity series ordered most to least
Potassium, sodium, calcium, magnesium, aluminium, carbon, zinc, iron, hydrogen, copper, silver, gold
The most reactive metals more easily become
Cations(positive ions) by losing electrons
Metals found in ores are
More reactive so arent foudn pure
Metals found in their pure state
Are less reactive so stay in their element
A metal ore is
A rock that contains enough metal to make it economcially worthwile to extract
The extraction of metal from ores involves
Reduction with carbon
Reduction of carbon for ores process
Carbon and the ore is heated and it reacts, so that the carbon replaces the less reactive metal in the compound, leaving the metal on its own.
It is called reduction with carbon because
Most ores are oxides of the metal, and reduction is the loss of oxygen
To be extracted using carbon reduction, the metal must be
Below it in the reactivity series
If a metal is more reactive than carbon it needs to be extracted by
Electrolysis
2 biological methods of metal extractiopn
Bioleaching and Phytoextraction
Bioleaching process
bacteria to extract. The bacteria uses energy that is holding the bonds together, so the metal is seperated. The solution formed called leachate contains metal ions that can be extracted using electrolysis and dispalcement
Phytoextraction process
Growing plants in soil that contains metal compounds. The metal is absorbed but not used, so builds up in the leaves. The plants are then burned to leave just the metal.
The more resistant a metal is to oxidation,
The lower it is in the reactivity series
Recycling metals advantages
Conserves resources and energy
Protects the environment
Economic benefits
Life-cycle assessments show
Total environmental costs of each stage of a products life
Stages of product life analysed during lifecycle assessments
Choice of material
Manufacture
Product use
Disposal
A reversible reaction is
When products can form reactants and reactants can form products, so the reaction goes both ways
As reversible reactions occur
The forwards and backwards reactions eventually reach the same rate so it is in equilibrium
Dynamic equilibrium is
When the forward and bacward reaction are happening at the same time and the same rate. The reactants and products concentrations isnt changing
Dynamic equilibrium can only be reached if the reaction is in
A closed system
Conditions that can change the position of the equilibrium
Temperature, pressure, concentration of reactants and products
The haber process is a
Reverisble reaction
What is the haber procees reaction
N2 + 3H2 –> 2NH3
Nitrogen for the haber process is from
The air
Hydrogen for the haber process is from
Hydrocarbons from natural gas and crude oil
The conditions used for the haber process
Temperature 450*
Pressure 200 atmospheres
Iron catalyst
Le chataliers principle states
When the conditions are chnaged in a reversible reaction, the equilibrium moves position to minimise the changes made
If temperature is decreased in a reversible reaction
The equilibrium moves in the exothermic direction because it wants to decrease the temp by giving more off
If temperature is increased in a reversible reaction
The equilibrium moves in the endothermic direction because its wants to absorb the extra heat
If pressure is increased in a reversible reaction
The equilibrium moves to the side with fewer moles of gas to reduce pressure
If pressure is decreased in a reversible reaction
The equilibrium moves to the side with more moles of gas to increase pressure
If concentration of reactants is increased in a reversible reaction
The equilibrium will move right to use up the reactants. Vice versa for decreasign conc of reactants
If concentration of products is increased in a reversible reaction
The equilibrium will move left to use up the products. Vice vers for decreasing conc of products
To increase yield in a reversible reaction
The equilibrium needs to move right
