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AQA Chemistry GCSE - Unit 1A - Products from Rocks
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- 1what two types of atoms are involved in IONIC bonding?metal and non-metal
- 2in IONIC bonding, which atom loses electrons to becomes POSITIVELY charged?the metal atom
- 3what does OIL RIG stand for?oxidation is loss, reduction is gain
- 4what two atoms are involved in COLVALENT bonding?both non-metal atoms
- 5what is limestone made of?calcium carbonate
- 6what does LIMESTONE form when THERMALLY DECOMPOSED?calcium oxide and carbon dioxide
- 7when acid is added to CALCIUM CARBONATE, what is formed?calcium salt, carbon dioxide and water
- 8what is produced when you react CALCIUM OXIDE with WATER?calcium hydroxide
- 9what is the test for CARBON DIOXIDE?bubbling it through limewater (calcium hydroxide)
- 10why in the test for CARBON DIOXIDE does the limewater become cloudy?because the carbon dioxide reacts with the calcium hydroxide to form calcium carbonate and water
- 11how is cement made?powdered limestone is heated in a kiln with powdered clay
- 12how is mortar made?cement is mixed with sand and water
- 13how is concrete made?cement is mixed with sand and aggregate (water and gravel)
- 14what are the cons of quarrying limestone?creates large ugly holes in the landscape
noise and dust pollution
destroys animals habitat
limestone needs to be transported away
waste produces ugly tips - 15what are the pros of quarrying limestone?can be used to build houses/roads
chemicals extracted are used in medicine
can be used to neutralise acidic soil/water
neutralises sulphur dioxide in chimneys
creates jobs
landscaping and restoration afterwards - 16what are the advantages of limestone products?can be used as perfect building materials
widely available/ cheap/ easy to cut
concrete can be moulded
fire-resistant/ doesn't rot
doesn't corrode - 17what are the disadvantages of limestone products?low tensile strength and can crack
ugly
will react with acid rain - 18what is an ore?rock which contains enough of the metal to make it worth extracting
- 19why might the economics of metal extraction change over time?if prices drop it might not be worth extracting more of it
as technology improves, we can extract metal which wasn't previously extractable and would therefore be worth it - 20what are the two different methods of extracting metal?electrolysis
reduction with carbon - 21how can you extract copper with reduction?heat in a furnace with carbon - smelting
- 22why is electrolysis often used instead for copper extraction?copper produced from smelting is often impure and this causes problems when used for electrical wiring - when impure copper is a poor conductor
- 23what is electrolysis?breaking down of a substance using electricity
- 24what is an electrolyte?a liquid required for the breaking down of a substance through electrolysis as it conducts the electricity
- 25what is an electrolyte usually made of?metal salt solutions made from the ore, or molten metal oxides
- 26how does the electrolyte conduct the electricity?it has free ions which are able to conduct the electricity
- 27which electrode take electrons away and which electrode gives electrons?positive - takes electrons away
negative - gives electrons - 28what is another method of extraction, beside electrolysis and reduction?displacement - where a more reactive metal is put in a solution of a dissolved less reactive metal compound. This works as the more reactive metal bonds more strongly with the to the non-metal part of the compound and therefore displaces the less reactive metal from the compound
- 29why is scrap iron often used in copper displacement reactions?because the iron is cheaper than the copper (which is very expensive) and the iron doesn't have to be 100% pure
- 30what are two different methods of extracting copper from the ground?bioleaching
phytomining - 31what is bioleaching?where bacteria is used to separate copper from copper sulphate. The bacteria gets energy from the bond between the copper and the sulphur, separating the copper from the ore. The leachate (solution produced) can be filtered to remove the copper
- 32what is phytomining?plants are grown in soil which contains copper. The plants can't use of get rid of the copper so it builds up in the leaves. The plants are harvested, dried and burned, and then the copper is removed from the ash
- 33why is recycling metals important?mining and extracting metals uses a lot of energy and this comes from fossil fuels - recycling only uses a fraction
saves money
finite amount of resources/ metal
reduces land fill - 34what properties do metals have?strong
malleable
conduct heat
conduct electricity - 35what are the two major problems with metals?they can corrode when exposed to air and need protecting
they can become 'tired' when repeatedly put under stress and strain and metal fatigue can occur where they then break - 36how does an alloy make a metal harder?the atoms, previously arranged in layers and able to easily slide over one another, are upset by different sized atoms of the other element/s and can therefore not slide over one another as easily = harder
- 37what is bronze made of and what is it used for?copper + tin
used for making medals and statues - 38what is cupronickel made of and what is it used for?copper + nickel
used for making 'silver' coins - 39what metals can be added to gold to make it better suited for jewellery?zinc/ copper/ silver/ palladium and nickel
- 40what is a mixture?two or more elements that are not chemically bonded together
- 41what are hydrocarbons?a chain of hydrogen and carbon atoms
- 42how are different hydrocarbon chains fractioned off using a fractional distillation column?the crude oil is vaporised
the gases rise up the column, cooling
they condense at their boiling points
shorter chains are fractioned off at the top
longer chains are fractioned off at the bottom, often not vaporising at all - 43what are alkanes?single bonds
saturated (carbon forms full 4 bonds)
CnH2n+2 - 44what are the properties of alkanes?shorter the molecule the more runny it is
the shorter the molecule, the more volatile it is (vaporise at a lower temperature) - lower boiling point
shorter the molecule, the more flammable it is - 45why is crude oil so important?it's our main source of fuel
major industry
source of raw materials - e.g. chemicals
everything is already set up for crude oil
easiest and cheapest option for fuel
more reliable than alternatives - 46what are the issues involved with crude oil suppliesthey're finite - non-renewable
we don't know when they'll run out
technology is improving allowing us to extract more oil than before
takes time to develop new energy sources - even though there are others - 47what are the three main sources of alternate energy that we use?solar
wind
nuclear - 48how does crude oil affect the environment?when it spills it pollutes the water
it poisons the animals living in the water
it covers their feathers and stops the water-proofing
contributes to global warming/ acid rain and global dimming - 49what are the problems with burning fossil fuels?when a fuel is burnt, carbon dioxide and water vapour are released
sulphur impurities also form sulphur dioxide
nitrogen oxides form at high temperatures - 50what happens when there is not enough oxygen in the combustion reaction - partial combustion?solid particles (particulates) of soot (carbon) are released and so is un-burnt fuel
carbon monoxide (poisonous) is also relased - 51what happens when sulphur dioxide is released into the atmosphere?when sulphur dioxide mixes with water vapour in the atmosphere, it forms sulphuric acid
this is the same with oxides of nitrogen - 52what are the issues with acid rain?causes lakes to become acidic and plants and animals die
limestone buildings are eroded, along with stone statues
acid rain has been linked to health issues - 53how can sulphur emissions be controlled?sulphur can be removed before the fuel is burnt (expensive)
car fuels are being replaced by low-sulphur versions
power stations have Acid Gas Scrubbers to take harmful gases out of fumes before they are released - 54how do particles cause global dimming?particles of soot and ash are produced when fossil fuels are burnt
these particles reflect sunlight back into space or help create clouds which also reflect sunlight back - 55what are three alternate fuels used for cars?ethanol
biodiesel
hydrogen gas - 56what are the pros and cons of ethanol?pros = carbon neutral/ only other product is water
cons = engines will need to be converted/ not widely available/ will use up crop spaces and therefore increase the price of food - 57how is ethanol made?plant material (known as bio-fuel) undergoes fermentation - often mixed with petrol to make a better fuel
- 58what is bio-diesel?produced from vegetable oils (rapeseed oil) it is another bio-fuel. It is also mixed with diesel to run a diesel engine
- 59what are the pros and cons of biodiesel?pros = carbon neutral/ engines don't need to be converted/ produces less sulphur dioxide and particulates than normal
cons = expensive/ can't make enough to replace diesel/ increases food prices - 60how is hydrogen made?hydrogen gas can be made through electrolysis of water
- 61what are the pros and cons of hydrogen gas?pros = hydrogen combines with oxygen to form water - clean
cons = needs a special expensive engine/ hydrogen isn't widely available/ still requires energy from another source/ hard to store as it is explosive
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- Questions from the AQA Chemistry GCSE Unit 1a.
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