Chemistry- Topic 4/ Extracting metals and equlibria Flashcards
How is sodium stored and why?
In oil because it reacts with oxygen
Properties of sodium
Dull, soft and shiny inside (where it hasn’t been oxidised)
Hydrogen test
Squeaky pop test
What substances are made when sodium reacts with water
Sodium hydroxide and hydrogen
What happens to lithium when placed in water?
It quickly moves around the surface and produces lithium hydroxide and hydrogen. pH is purple
What happens to sodium when placed in water?
It melts into a ball and quickly moves around the surface, producing sodium hydroxide and hydrogen. pH blue
What happens to when potassium placed in water?
It quickly moves around the surface and produces potassium hydroxide and hydrogen, the hydrogen becomes a lilac flame due to heightened amount of heat. pH purple.
What happens to when rubidium placed in water?
Rubidium immediately sparks, producing rubidium hydroxide.
What happens to when caesium placed in water?
caesium immediately sparks and flies off, producing caesium hydroxide and hydrogen.
What happens to calcium when calcium placed in water?
Calcium fizzes and produces a cloudy solution as it is only partly soluble. This saturated, is lime water.
Displacement and redox.
A displacement reaction causes both reduction (gains electrons) and oxidation (lose of electrons)
Reactivity series
Potassium
Sodium
Lithium
Calcium
Magnesium
Aluminium
Carbon
Zinc
Iron
Tin
Lead
Hydrogen
Copper
Silver
Gold
Platinum
How are metals extracted
In ores from the earth and unreactive metals are found in the earth’s crust as uncombined elements
Oxidation
When an atom with with less than 4 electrons on its outer shell loses electrons to have a complete outer shell. This also includes a gain of oxygen and loss of hydrogen
Reduction
When an atom with with more than 4 electrons on its outer shell gains electrons to have a complete outer shell. This also includes a loss of oxygen and gain of hydrogen
How does reduction extract metal from ores
Reduction reaction takes the oxygen from the ore leaving the metal
How does carbon extract metals such as iron
The carbon is burned with oxygen to produce carbon dioxide, this then reacts with more carbon forming carbon monoxide carbon monoxide then reduces iron.
2Fe2O2+3C=3CO2+ 2Fe2
Chemical name of Malachite
Copper carbonate hydroxide
Metal + Acid
Salt + hydrogen
Acid + Metal Hydrogen Carbonate
salt + water + carbon dioxide
Acid + Metal Carbonate
Salt + water + carbon dioxide
Acid + Base
Salt + water
Sulfuric Acid
H2SO4
Hydrochloric Acid
HCI
Nitric Acid
HNO3
What is Aluminium used for
Drink cans and areoplanes
What is aluminium mixed with to lower its boiling point
cryolite
How does the electrolysis work and what has to be replaced
The molten aluminium oxide’s positive atoms (aluminium 3+) is attracted to the cathode whereas the negative oxygen 2- is attracted to the positive anode. The cathode and Anode are made of graphite and therefore the anode has to be replaced regularly because the graphite (carbon reacts) with the oxygen forming co2
Aluminium in electrolysis half equation
Aluminium 3+ + 3e- = aluminium
Oxygen in electrolysis half equation
Oxygen 2- = Oxygen + 2e-
Why is graphite used in an electrolysis
Because it has a high melting point and is good at conducting electricity
High grade ore
Has a high quantity of metal
low grade ore
Has low quantity of metal
Why is mining copper problematic?
1) Copper acid can pollute nearby water
2)Land destroyed
3)Deforestation
Phytoextraction
Plants absorb metal compounds from the soil, they store this and they are burnt to form ash. In the ash is a high concentration of metal
Bioleaching
Bacteria is mixed with the low grade ore producing leachate. The copper compounds are then purified by displacement with iron or an electrolysis.
Phytoextraction Positives
-No harmful gasses
-less damage to landscape
-conserves suppliers of high grade ore
-extracts metals from contaminated soil
Bioleaching positives
-No high temperature needed
-No harmful gasses
-Less damage to landscape
-conserves suppliers of high grade ore
Phytoextraction Negatives
- Takes a long time
- depends on weather
- expensive
Bioleaching negatives
-Sulfuric acid is produced, toxic to the environment
Advantages of recycling metals
- Reserves metal
- Less mining
- Less pollution
- Less energy than extracting
- Less waste metal
Negatives of recycling metals
- Costly
- ## Lots of energy to transport and collect
Plastic bag disposable
- Recyclable
- Not biodegradable
- Pollutes land
- Landfills
Paper bag disposable
- Biodegradable
- recyclable
- Not toxic
How are metals recycled
They are collected and melted and re-shaped.
