C1 Atoms And Products From Rocks and oil. Flashcards
What does the top number on a periodic table symbol mean?
The mass number. The total number of protons and neutrons.
What is an element?
A thing made of only one type of atom.
What does the bottom number on a periodic table symbol mean?
It is the atomic number. This is the number of protons which also tells you the number of electrons.
How do you find the number of neutrons of an atom?
Subtract the atomic number from the mass number.
Why are ions attracted to each other?
They from an ionic bond as they are of opposite charges and so are attracted to each other.
What is a compound that forms from two non-metals?
A covalent bond.
What is limestone?
Calcium carbonate. CaCO”3”
What happens when calcium carbonate thermal decomposes?
Calcium carbonate = calcium oxide + carbon dioxide.
CaCO”3”. CaO. CO”2”
What happens when magnesium, copper, zinc or sodium carbonates are heated?
They will thermally decompose in the same way calcium will.
What happens when calcium carbonate is reacted with acid?
A salt, CO2 and water will be made.
Calcium carbonate+ sulphuric acid=calcium sulphate + CO2+H2O
CaCO”3”. H”2”SO”4”. CaSO”4”
The salt created will depend on the acid used.
What happens when water is added to calcium oxide?
CaO + H”2”O = Ca(OH)”2”
Calcium hydroxide will be made.
What can calcium hydroxide be used for?
It is an alkali so it can be used to neutralise acidic soil in fields. Powdered limestone can be used for this as well but the hydroxide works faster.
Also, if it is mixed with water you get limewater which can detect CO2
What happens when calcium hydroxide is mixed with carbon dioxide?
Calcium hydroxide + CO”2” = calcium carbonate + water.
Ca(OH)”2”. CaCO”3”. H”2”O
How can limestone be used in construction?
Powered limestone is heated in akin with powdered clay to make cement.
Cement can be mixed with sand and water to make mortar. Mortar is the stuff used to stick bricks together. Calcium hydroxide can also be used.
Or cement can be mixed with sand and aggregate to make concrete.
What is a problem with quarrying limestone?
It makes huge ugly holes which alter the landscape.
Quarrying processes make lots of noise and dust in quiet scenic areas.
It destroys the habitats of animals and birds.
The limestone needs to be transported away. This causes noise and pollution.
Waste materials produce un slightly tips.
How does using limestone cause pollution?
Cement factories make a lot of dust which can cause breathing problems.
Energy is needed to produce cement and quicklime. The energy will come from burning fossil fuels.
What are the positives of mining limestone?
It can be used to build things.
Limestone can be used to neutralise acidic soil or acidic rivers.
It it neutralise sulphur dioxide which is produced by power stations.
Quarrying provides jobs and adds money to the local economy.
Landscaping and restoration of the area is normally required as part of the planning persission.
What are the pros of using limestone?
It is widely available and cheaper than granite or marble. It is easy to cut.
It looks attractive and can be more hard wearing than marble.
Concrete can be poured into moulds to make blocks. It is quick and cheap but very un attractive.
It’s fire resistant, doesn’t rot and can’t be gnawed by animals.
Concrete doesn’t corrode. It has a very low tensile strength which can be improved by steel bars.
What is an ore?
A rock with enough of an element in it for it be economically viable to extract it.
How can the economics of metal extraction change?
If the market price drops, it might not be worth extracting it.
If the price goes up, it might be worth extracting more of it.
As technology improves it can make extracting metal cheaper.
How can a metal be extracted from an ore?
It can be done chemically by reduction or by electrolysis.
Some ores may have to be concentrated before extraction.
Electrolysis can be used to purify the extracted metal.
How can some metals be extracted by reduction with carbon?
Oxygen will be removed from the ore.
2Fe”2”O”3” + 3C = 4Fe + 3CO”2”
The Metals will have to be less reactive than carbon for this to work.
Why is electrolysis used to extract certain metals?
They are more reactive than carbon so can’r be displaced.
Why is copper purified with electrolysis?
It is extracted with reduction with carbon when it is smelted.
However this isn’t very pure.
It is electrolysed so as to purify it so it is a better conductor.