Summary of Chemistry C1a aqa

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Chemistry Unit C1a
The effects of extraction
Digging out rocks leave big holes ­ quarries. Limestone is often found in scenic areas such as the peak
What are the advantages/disadvantages of quarrying?
Provide local employment.
Provides us with limestone which is used for building materials.
However quarrying:
Reduces tourism-people don't like it
Spoils natural beauty of landscape
Produces noise pollution-lorries etc.
Limestone is made up of three different types of atoms: Calcium (Ca), Carbon (C), and oxygen
(O2). Limestone makes a chemical compound called calcium carbonate (CaCo3). Limestone
is used for:
Buildings or road chippings
To neutralise excess acid in lakes or soils.
To make cement
In other industrial processes.
If limestone is heated strongly, the compound breaks up and the atoms are re-arranged. This
forms quicklime. The breaking down of a compound by heating it is known as thermal
Quicklime is a very strong alkali, when reacted with water it forms slaked lime/Calcium
hydroxide. Farmers use slaked lime to neutralise soils.
Mortar was originally used to stick bricks together for houses. Mortar is made from slaked
lime and water. (Mixed)
Today most limestone is used for Cement. Cement is made by heating limestone in a rotary
kiln. It is used instead of mortar, and when mixed with sand, gravel and water it forms
Concrete. To make concrete stronger steel is added, to prevent cracking.
Glass is formed when limestone is heated with sand and a little soda (Sodium Carbonate).
Calcium carbonate (limestone) + Silicon dioxide (Sand) Calcium Silicate (Glass) +
Carbon dioxide.

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Atoms have a small central nucleus. Orbiting this nucleus are the tiny electrons. It is the
moving electrons that give atoms their shape.
When a chemical reaction takes place between atoms, electrons may move from one atom
to another or be shared between atoms.
When metals and non-metals combine the metals give up some electrons and the
non-metals take them. E.g.…read more

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Iron is extracted from its ore by the Blast furnace. When the reaction is complete it
produces Cast iron which is 96% pure iron and 4% carbon & other impurities. Nowadays it is
too brittle for most uses.
In a pure metal atoms are stacked up the same. They are held strongly together however
they can slide over each other if force is acted on them. In an Atom few atoms have been
added, these are not the same size as the rest though.…read more

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Future Fuels: Oil will eventually run out, Hydrogen is being developed for use with buses.
When Hydrogen burns it produces water so therefore it is completely pollution free.
Hydrogen + Oxygen Water + Energy
Advantages and Disadvantages for using ethanol as fuel for cars.
Clean, Renewable
Halves or cuts down the use of oil- therefore betters the environment
Large areas of rainforest have been cut down.
Chemistry Unit C1b
Plastics are easy to use in a large scale industrial process.…read more

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All Alkenes have double bonds and are unsaturated
Alkanes No. Of Carbons Alkenes
Methane 1 Methene
Ethane 2 Ethene
Propane 3 Propene
Butane 4 Butene
Pentane (CnH2+2) 5 Pentene (CnH2x)
Ethene has many uses and can be made into a range of things from ethanol to plastic.
Ethene is a waste product when making more petrol from long-chained hydro-carbons;
chemists have discovered that when Ethene is reacted with Steam is produces ethanol.…read more

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Smart Polymers are polymers specifically designed for certain tasks, for example shape
memory polymers, which under heat can be stretched and when cooled they will stick in
their new shape. The polymer can then return back to it original shape after it is heated again.
Extracting Oil from Plants/Oils (Continued)
Oil can be extracted by industrial hydraulic presses, or by distillation.
Bromine water is an orange-brown solution and is the test to show whether something is
unsaturated oil (C=C).…read more

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An emulsion is a mixture of tiny droplets of oil in water or water in oil. They do not mix, and
if you let them stand they will separate. Emulsions are thicker than water.
Emulsifiers prevent these foods separating out. For example Egg yolk prevents oil and
vinegar from mayonnaise separating. These emulsifiers have a whole set of E-Numbers to
themselves. E-322-499 are all emulsifiers
We can tell what is in our food by separating out the chemicals in them.…read more


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