C1 Flashcards
Name a use of limestone
It is used as a building material and to make calcium oxide and cement
How do you make concrete
mix sand with water, cement and aggregate
what happens when calcium carbonate is heated?
It decomposes and makes calcium oxide and carbon dioxide
What happens when metal carbonates are heated?
They decompose and produce metal oxide and carbon dioxide
what is the effect when co2 and limewater are mixed
it turns cloudy
What is the first step of the limestone cycle?
Calcium carbonate is heated to make calcium oxide, carbon dioxide is given off
What is the second step of the limestone cycle?
a little bit f water is added to calcium oxide to make calcium hydroxide
What is the 3rd step of the limestone cycle?
A little water is added and it is filtered to make limewater/calcuim hydroxide solution
What is the 4th step of the limestone cycle?
Co2 is added to the solution (this is the test for CO2)
How is cement made?
Limestone is heated in a kilm
How is mortar made?
cement and sand are mixed with water
Name some advantages and disadvantages for the area near a limestone quarry
- More employment for local people
- Dust and noise
- More traffic
- Loss of habitat for wildlife
- More customers and trade for local businesses
- Improved roads
What is an ore?
Rock that contains enough of a metal or a metal compound to make it worth extracting.
How are metals seperated
Some metals that are low in the reactivity series can be separated physically, however most metals are found in compounds so haft to be extracted by chemical reactions
How can metals be extracted from compounds?
Metals can be extracted from compounds by displacement using a more reactive element. Metals which are less reactive than Carbon can be extracted from their oxides by heating with carbon.
Why does cast iron from a blast furnace only have a few uses?
Because it is hard and brittle and only contains 96% pure ironthe rest is impurities
What are most iron used to make?
Steels, they are alloys of iron because they are a mixture of iron carbon and other elements.
Whats so good about alloys
they can be made so that they have properties for specific uses
Why are aluminium and titanium expensive?
Because extracting them involves many stages and requires large amounts of energy
Why is titanium used for aircraft?
it is used for aircraft because it is very strong, also it is resistant to corrosion. It also has a low density compared to other metals
How is most copper extracted?
it is extracted from copper rich ores by smelting
How can copper be purified?
Electrolosys
Name 2 new ways to extract copper from low grade ores.
Bioleaching and phytomining
What are transition metals?
Metals that are found in the centre block of the periodic table, they have properties that make them useful for building and making things, most of the metals we use are alloys
What is limestone mainly made out of
calcium carbonate
What is crude oil?
A mixture of many different compounds that boil at different temperatures most of these are hydro carbons
what is a hydrocarbon
A molecule that contagion only hydrogen and carbon, many of these are alkanes, they contain as many hydrogen atoms as possible in each molecule so we call them saturated hydrocarbons
How is crude oil separated?
crude oil is separated using fractional distillation, this uses the different boiling points of the hydrocarbons the evaporate to different levels of the fractionating column
what happens when pure hydrocarbons burn completely?
They are oxidised to carbon dioxide and water
What are biofuels
Biofuels are made from plant or animal products and are renewable. Biodiesel can be made from vegetable oils extracted from plants.
What are the advantages of biofuels
it makes little contribution to carbon dioxide levels, this is because the carbon dioxide given off when it burns was taken from the atmosphere by plants as they grew.
What are the disadvantages of biofuels
The plants that grow for biodiesel use large areas of farmland
What is cracking?
Large hydrocarbon molecules can be broken down into smaller. molecules by a process called cracking, it can be done in two ways, -by heating a mixture of hydrocarbon vapours and steam to a very high temperature
-by passing hydrocarbon vapours over a hot catalyst.
What happens during cracking?
Thermal decomposition reactions produce a mixture of smaller molecules. Some of the smaller molecules are alkenes. Alkenes are unsaturated hydrocarbons because they contain fewer hydrogen atoms than Alkenes with the same number of carbon atoms
What is the difference between Alkenes and alkanes
Alkenes have a double bond between two carbon atoms and this makes them more reactive than alkanes. Alkenes react with bromine water turning it from orange to colourless.
What are polymers made of?
Very small molecules joined together, the small molecules used to make polymers are called monomers.
What is the reaction to make polymers?
Polymerisation
how many monomers are in a polyethene molecule?
Lost of ethane molecules join together in one big chain
Why can we make polymers from Alkenes but not alkanes?
Because only Alkenes can polymerise in a similar way
What is a shape memory polymer?
A type of smart polymer that changes beck to its original shape
give 4 uses of polymers
Fibres used to make fabrics can be coated by polymers to make them waterproof and breathable, the plastic used to make many drinks bottles can be recycled to make polyester fibres for clothing as well as fitting pillows and duvets
How would losing biodegradable polymers help with the problem of plastic litter,
these plastic bags have plastic that microorganisms can break down when it comes in contact with soil
Describe 2 ways that cornstarch can be used to help with problems of disposal of plastic waste
Cornstarch can be mixed into the plastic so it is easier for it to decompose. also it is used to make biodegradable plastic bags, by being mixed with vegetable oils
write a word equation for the fermentation of sugar using yeast
enzymes is the yeast cause the sugar to convert to ethanol and carbon dioxide, this method is used to make alcoholic drinks
how can vegetable oils be extracted from seeds, nuts and fruits
they can be extracted by pressing or distillation
What can vegetable oils provide and what are they for?
They provide nutrients and a lot of energy and they can be used to make biofuels.
why are some vegetable oils described as unsaturated?
because they contain carbon carbon double bonds, if there are several they become polyunsaturated, they react with bromine water, turning it orange to colourless
why. are vegetable oils useful in cooking?
because of their high boiling points
what affect do vegetable oils have on foods
they increase the energy content of the foods, change the flavour, colour and texture of the food
how can vegetables be converted to solids
they are reacted with hydrogen at 69 decrees C with a nickel catalyst.
how can your recognise an emulsion?
they are opaque and thicker than the oil and water they are made from.
What are emulsifiers?
they are molecules that stop 2 things from seperating into 2 layers
how do emulsifiers keep the mixtures seperate?
they have a hydrophilic head and a hydrophobic tail so the droplets are always surrounded by these
name the 3 layers of the earth
the core, the mantle and the crust
what makes tectonic plates move?
convection currents in the mantle cause the plates to move a few cm per year
why can’t scientists predict when earthquakes will happen?
because they do not know enough about what is happening
what were Alfred Wegeners ideas and why weren’t they accepted?
His theory was continental drift but it wasn’t accepted because he couldn’t explain it
what causes convection currents?
energy released by the decay of radioactive elements in the mantle
How was the earths early atmosphere formed and what did it contain?
by volcanic activity, it probibly contained mainly of carbon dioxide but there may have been water vapour together with traces of methane and ammonia
how did oxygen levels rise in the earth?
by. plants spreading around it
What happened to most of the co2 in the early atmosphere?
It became locked up in sedimentary rocks
what is the proportion of gases in the atmosphere
78% hydrogen 20% oxygen 0.04% argon 0.9% co2 and traces of other gases are present
why can the gases in air be separated by fractional distillation?
Because they all have different boiling points
in human activity which has been the most carbon emitting?
burning fossil fuels
