Chemistry OCR GCSE C2 (higher)

• Pigment - colourd powder / rock
• BInding meium - glue to bind pigment
• Solvent - Thins the paint
• Colloid - pigment dispersed in liuqid 

Thermochromic paints

Thermochromic paint changes colour whe the temperature changes. it can be used for babies baths to test temperature or beer cans to test if they are cold enough.

Phosperesent paint

phosphorecent pigments absorb energy from daylight. then slowly release the energy as light. It can be used for stars glowing in a childs bedroom at night or road signs.

Synthetic dye

sythetic dye is a man made colouring for textiles. can be used in clothes and funtiture. they are mutch brighter than natural dye.

1. What undesirable property did the eirliest phospherescent paints have?

Radioactivity.

2. Describe what happens when a gloss paint is applied to a window frame and allowed to 'dry'

The paint coats a surface with a thin layer and the solvent evapourates leaving the colour.

Construction materials

Granite, marble, limestone, iron, aluminium, brick, cement, glass, concrete, are all construction materials.

Raw materals

Raw materials are materials from the ground that have been turned into building materials. e.g. clay (raw material) is turned to brick (building material)

Calcium carbonate

Calcium carbonate thermally decomposes at a very high temperature Calcuim

carbonate = calcium oxide + carbon dioxide

1. Fill in the gaps

Iron and aluminium are ................  that are extracted from rocks called ..........

Iron is extracted from a rock that contains the iron combined with oxygen. The chemical name is iron ........

2. What is thermol decomposition?

A type of reaction where one material breaks down into two new substances when it is heated.

Lithophere

The earths lithosphere is relitively cold and rigid. It consists of the crust and the outer part of the mantle. 

Volcanoes

Volcanoes form where molten rock (magma) from the bottem of the mantle, where it is hotter can find it way through gaps in the earths lithosphere. The flow from the magma in the top of the mantle pushes the plates apart to make way for the magma, now lava to come out of the earth.

Did you know?

• when magma is cooled fast it makes Basalt and Rholite
• When magma is cooled Slowly it makes granite and gabbro

1. Name two rocks formed from cooled lava/magma:

• Granite
• Basalt

2. how do the two named differ in apearance?

Granite is very hard and basalt is softer.

3. What is subduction?

Subduction is where

4. Explian why earthquakes are not very common in britain:

Becuse we are in the middle of a tectonic plate and earthquakes are more common on the edge of plates.

Alloys

An alloy is a mixture of metal with something else usually another metal. Alloys e.g. bronze and steel re made to improve the metals and make them more usefull. They are often harder and stronger than pure metals. Amalgam is made using mercury and is used for fillings in teeth. Brass is made of copper and zinc and used in door handels and ornaments, Solder is made of lead amd tin and is used to join pipes and wires.

Electrolysis

Electrolysis is the name given to a chemical reaction that uses electricity. The electricity is then passed through a liquid or solution called an electrolyte e.g. copper (II) sulphate used to purify copper. Electrodes are used to connect to the electrolyte . The positive electrode (anode) is made of bolder (impure copper) and the negative electrode (cathode) is made of pure copper.

1. What is a smart alloy?

A smart alloy such as Nicol (an alloy of nickle and titanium) can be bent and twisted but it will return to its original shape when it is heated. It has shape memory. Many new uses are still being developed for this type of alloy.

2. Explain what electrolysis is:

Electrolysis is the breaking down of a compound, made of ions, into similar substances using an electric current. During electrolysis ions gain or loose electrons at the electrons and electrodes, forming electrically neutral atoms or molicueles witch are then released.

Rusting

Rusting is an example of an oxidation reaction. This is a reaction where oxygen is added to a substance. Oxygen is added to the iron in the presence of water. The equasion for rusting is.

Iron + oxygen + water = Hydrated iron (III) oxide

Catalyst converters

to help reduse the amount of pollutants being put into the atmosphere, catalyst converters are fitted to cars to convert the carbon monoxide in exahust gases to the less harmfull carbon dioxide.

Carbon monixide + hydrogen = Nitrogen + carbon dioxide

2CO                     +   2NO      =      N2     +         2CO2

1. Describe what these materials are used for in a car and why:

• Nylon - Seat Belts - strong and flexible
• Glass - Windscreen - Transparent
• Copper - Wiring in engine - good electrical conductor
• Aluminium alloy - Wheels - Light weight and dont corrode
• Steel - body - Strong and malleable
• Plastic - Trim - Rigid and does not corrode.

2. Why are the materials in cars recycled when they are scrapped?

Because the law says that 85% must be recyled and reclycling the materials like plastics and fibers reduces the amount of crude oil needed to make them and therefore conserves oil refinarys.

The earths atmosphere has evolved over time. clean air contains 78% nitrogen, 21% oxygen,  and 1% other gaseslike carbon dioxide, methane and carbon monoxide.

RESPERATION decreases oxygen levels and increases carbon dioxide levels in air.

PHOTOSYTHESIS decreases carbon dioxide and increases oxygen levels in the air.

Pollutant gases are formed from...

• the burning of fossil fuels
• incomplete combustion in a car engine

Acid rain

Acid rain is formed when coal or oils are burned, the sulpher impurities produce sulpher dioxide. it then dissolves water to make acid rain.

1. For each of the below indicate what pollutions problem it causes:

• Carbon dioxide - leads to global warming
• Carbon monoxide - harmufull to humans
• Sulpher dioxide - leads to acid rain
• Nitrogen dioxide - leads to acid rain
• CFC's - Damage ozone layer

2. Give three ways humans have effected the enviroment:

• Burning fossil fuels
• Deforestation
• Increase in population 

There are four important factors which effect the rate of reaction

• Temperature (particles move faster at high temp)
• Concentration (more collissions at high concentration)
• surface area (larger surface area faster reaction)
• Use of a catalyst (incresases the rate of reaction)

Catalysts

• Catalysts are specific to ertain reactions, a catalyst for one reaction wont work for another one.
• Catalysts are very usefull as only a small amount of catalyst is needed to speed up a reaction.

1. select the correct word:

Powered Limestone has a small/large surface area in relation top its volume

A lump of limestone has a large/small surface area in relation its volume

Powders react faster/slower than lumps

2. What is an explosion?

An very fast reaction where huge amounts of gases are prduced

3. Titanium is used to make aeroplanes

It's Iightweight and the strongest metal, it also has a low density and a high melting point.