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| Question | Answer |
| C1 | C1 |
| What gases does the air contain? | 78% nitrogen, 21% oxygen, 1% other |
| What does oxygen react with most metals to make? | Solid metal oxides |
| When and how was Earth's atmosphere created? | About 4billion years ago by gases produced by volcanoes. |
| List the stages of the atmosphere | 4billion years ago the Earth's atmosphere was very hot. As the Earth cooled, oceans formed. 3billion years ago, bacteria formed that used photosynthesis. CO2 was removed by the bacteria and released oxygen. Animals started to evolve. Animals dying and being buried helped remove CO2. Buried material became fossil fuels over millions of years. CO2 dissolves in oceans, reacting with salts and creating Calcium Carbonate. This forms sediments which are buried to create rocks. |
| What did scientists believe to Earth's early atmosphere was made of? What do they now believe? | Used to think it was made of ammonia and methane. Now believe it was mainly made up off CO2 |
| Examples of pollutants | Carbon monoxide, nitrogen oxides and sulphur dioxide. |
| What are the dangers of CO to humans and animals? | Reduces the amount of oxygen in the blood. |
| What is the definition of 'good' air quality? What is the definition of 'poor'? | Good: Few pollutants. Poor: Lots of pollutants. |
| What is the result of burning fuels? | Releases CO2 and particulates. Especially soot. |
| How does CO2 link to climate change? | Uses the greenhouse effect to create a layer and trap heat in the atmosphere. |
| Poor pollution can cause humans to die from... | Asthma, heart disease and lung disease. |
| What makes acid rain? | Sulphur dioxide and nitrogen dioxide. |
| What are small amounts of CO2 measured in? | parts per million (ppm) |
| What are other pollutant gases measured in? | Parts per billion (ppb) |
| Where is air pollution measured at? | Monitoring stations, data is then transmitted to a central computer to be analysed. |
| What is oxygen needed for in burning? | To release energy |
| What contain hydrocarbons? What do they use it for? | Anything with hydrogen and carbon. Petrol, diesel and fuel oil. |
| What is coal made up of? | Carbon atoms |
| The equation for hydrogen burning | hydrogen fuel + oxygen ----> carbon dioxide + water (+ energy) |
| Define oxidation | When oxygen is added to a substance. |
| Define reduction | When oxygen is removed from a substance |
| Define combustion | An oxidation reaction |
| What do atoms or non metals form to make? | Molecules |
| What happens when sulphur is burned? | Makes a colourless gas called Sulphur dioxide |
| What happens when sulphur dioxide reacts with water? | An acid solution |
| Acid rain is an indirect or direct pollutant? | Indirect |
| What is always formed when fuel is burned? | CO2 |
| What happens when there isn't enough oxygen when burning? | Carbon monoxide and soot is made. |
| What gas do cars make at high temperatures? | Nitrogen oxides |
| Carbon monoxide and carbon particulates are created when what reaction occurs? | Incomplete combustion |
| Which fuels make less sulphur dioxide when burnt? Coal, or oil and gas. | Oil and gas |
| How can we get rid of poisonous gases in power stations? | Electrostatic filters |
| How can we get rid of sulphur dioxide? | Wet scrubbing |
| What are the two methods of wet scrubbing? How does it work? | Using an alkaline slurry or using sea water, which has natural alkaline. The alkaline neutralises the acid in sulphur dioxide. |
| Name ways to reduce the use of fossil fuels. | Using alternative energy sources, improving building insulation, and reducing our use of cars. |
| What are biofuels? | Biofuels are made from plants. They are burned to create energy, and are a more environmentally friendly version of fossil fuels. They can come as wood chips, palm oil, and alcohol made from sugar. |
| What's the definition of sustainable? | A material that we can take now without damaging the Earth for, or future generations. |
| What happens in a catalytic converter? | Allows pollutant gases to react with each other. carbon monoxide + nitrogen monoxide ---> nitrogen + carbon dioxide |
| C2 | C2 |
| Define melting point | Temperature a solid turns into a liquid |
| Define tensile strength | The force needed to break a material when stretched |
| Define compressive strength | The force needed to crush a material when squeezed |
| Define stiffness | Force needed to bend a material |
| Define hardness | How well a material stands to wear. |
| Define density | The mas of a given volume of a material. |
| What does effectiveness and durability of a product rely on? | The materials used to make it. Some can be spun or woven into thread. |
| Define the properties of metals | Shiny, malleable and electrical conductors |
| Define the properties of ceramics. What are they? | Ceramics are hard and strong. Examples are clay, glass and cement. |
| What are polymers? | Large molecules used to make rubbers, plastics and fibres. |
| What is concrete made up of? | Sand and cement |
| What is bronze made up of? | Copper and tin |
| Name some natural materials from living things | Cotton, paper, silk, and wool. |
| Name natural materials from the earth? | Limestone, iron ore, and crude oil. |
| What is crude oil made up of? | Thousands of hydrocarbons. |
| How are synthetic materials made? | They are manufactured by chemical reactions using raw materials. |
| Give reasons why synthetic has replaced some natural materials? | Natural materials are in short supply, synthetic can be designed for suitable properties, they're cheaper and they can be made in demand. |
| What are the processes of fractional distillation? | 1) Oil is heated up, turning it all into gases. 2) As the distillation tower gets higher, it gets cooler. 3) Liquids with similar boiling points are collected together. These are fractions. |
| What increases as the hydrocarbon chain lengthens? | The force between molecules. |
| How is a polymer made? | Polymerisation |
| What makes polyethene? | Ethene |
| What does PET make? What are the properties? | Drinks bottles. Clear, strong, low density, and doesn't shatter. |
| How do you alter polymer chains? | Replacing hydrogen atoms with other atoms. |
| Are forces stronger when polymers are further or closer apart? | Closer |
| What happens with a stronger force? | More energy is needed to separate them and there is a higher melting point. |
| What properties do Low density polyethene have? | Long molecules with branches. Make them weak, flexible, soft, and have low melting points. |
| What properties do high density polyethenes have? | Long chains without branches; molecules are aligned close together. Stronger, hard, and stiff. |
| What are plasticisers do? What do they do? | They are small molecules are inserted into the chains to keep them apart; weakening the forces between them. Make a polymer softer. |
| What do thermoplastics do? | They are heated and can be moulded into shape. |
| What do thermosetting plastics do? | They don't melt or soften when heated. They contain crosslinks which lock the molecules into place. |
| What happens when crystallinity is increased? | Is increased by removing branches, making the chains as flat as possible. This is so the chains can line up neatly. |
| What is the width of a human hair? | 0.1mm |
| What are nanoparticles? | Materials containing upto thousands of atoms. |
| How are nanoparticles created? | Naturally, such as salt. Accident, such as solid particulates. Can be designed in labs. |
| What is nanotechnology? | The control of very small structures. |
| What are buckyballs? | Very strong carbon spheres made up of 60 carbon atoms. |
| What are silver nanoparticles used for? | Killing bacteria. Can be found in plasters and socks. |
| What are titanium oxide nanoparticles used for? | For sunscreen. They are transparent and absorb light. |
| What are the risks of nanoparticles? | Silver nps can be washed out and end up in our sewers. Causing friendly bacteria used to purify water to be killed. Effects of nanoparticles have not been fully explored. |
| C3 | C3 |
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