Flashcards in Extracting metals and Equilibria Deck (43):
What happens when something gains oxygen?
It becomes oxidised.
Which are the 3 most reactive/least resistant to oxidising metals in the reactivity series?
Potassium, Sodium, Calcium
Which are the 3 least reactive/most resistant to oxidising metals in the reactivity series?
Gold, Silver, Copper
What do metals beneath hydrogen not do?
React with dilute acids as they are less reactive than Hydrogen.
How can you tell how reactive a metal is?
By working out how easily the metal loses its outer shell electrons to form positive ions.
The more reactive a metal is (in acid),...
...the faster the reaction will go; e.g fizzing vigorously
Less reactive metals react better with what?
What is a displacement reaction?
- A more reactive element takes place of the less reactive element in a compound.
What is a metal ore?
A rock which contains enough metal to make extraction economically worthwhile.
How is an ore extracted with carbon?
Oxygen is removed by reduction
Why are ores above carbon in the reactivity series not extracted with carbon?
The ore being extracted has to be less reactive than carbon as it can only take oxygen away from those ones.
Which metals are extracted via electrolysis?
Potassium, Sodium, Calcium, Magnesium, Aluminium.
Which metals are extracted via carbon?
Zinc, Iron, Tin, Copper, Silver
Which metals are found as uncombined elements?
Silver and Gold
How are metals extracted by electrolysis?
An electric current in passed through, causing the metal to be discharged at the cathode and non-metal at the anode.
Why is electrolysis extraction so expensive?
The metals require a lot of energy to extract, so it is costly to get the power. There is also an added cost of melting/dissolving the metal so it can conduct electricity.
Why are we looking for biological methods for metal extraction?
- demand is growing; shortages in the future
- use less energy
What is bioleaching?
Using bacteria to separate metals as bacteria take energy from the bonds between atoms, and once it is gone they separate.
What is phytoextraction?
Growing plant that contain metal compounds, as they gradually build up in the leaves. The leave can then be dried and burned - so the ashes contain to metal ashes to be arranged with electrolysis.
What are the problems and consequences with fossil fuels?
THEY ARE NON RENEWABLE AND RUNNING OUT:
- when burnt, very polluting
-> cause acid rain and climate change
How does recycling protect the environment?
Cuts down on rubbish sent to landfill, which takes up space and pollutes.
How does recycling benefit the economy?
- recycle expensive/rare metals
- industry creates lots of jobs
- saves money as it doesn't require so much energy
What is a life cycle assessment?
An assessment that looks at each life stage of a product and calculate total environmental impact and cost.
Choice of materials:
- mined/extracted; pollution
- raw materials; often from crude oil (non-renewable)
- energy use
- waste disposal
- water use
- Paint; toxic fumes
- Burning fuels; greenhouse gases
- Fertilisers; leach into water sources and damages ecosystems
- products often disposed in landfill which takes up space and pollutes
- incineration pollutes the air
What is a reversible reaction?
A reaction where products
What is the Haber process?
A reversible reaction:
Nv2 + 3Hv2 2NHv3
Where is Nitrogen sourced?
From the air
Where is Hydrogen sourced?
Extracted from hydrocarbon such as crude oil and natural gas.
What conditions is the Haber process carried out under?
> 450 degrees celsius
> 200 atmospheres
> an iron catalyst
How do reversible reactions reach equilibrium?
As reactant conc falls, forward reaction slows.
As product conc rises, backwards reaction speeds up.
After a while, the forward reaction will perform at the same rate as backwards - THIS IS EQUILIBRIUM.
What is dynamic equilibrium?
Forward and backwards reactions are performing at the same time and rate; concentrations are same and won't change.
Why can't equilibrium be reached in an open system?
Because reactants and products can escape, so it'll never balance.
When equilibrium lies to the right...
...there are more products than reactants.
When equilibrium lies to the left...
...there are more reactants than products.
What 3 things can change position of equilibrium?
- Pressure (in a gas)
- Concentration (of product or reactant)
What is the formula of a reversible reaction?
A + B C + D
( means forwards or backwards in this deck)
What does Le Chatelier's principle state?
If there is a change in concentration, pressure or temperature in a reversible reaction, equilibrium will move to counteract it.
Changes to temperature:
INCREASE - equilibrium moves in endothermic direction to absorb extra heat.
DECREASE - equilibrium moves in exothermic direction to absorb extra heat.
Changes to pressure:
INCREASE - equilibrium moves to side with less moles to reduce pressure.
DECREASE - equilibrium moves to side with more moles in increase pressure.