Term
| How are fractions from crude oil broken down? |
|
Definition
| By thermal decomposition in a catalytic cracker. It is vaporised and passed over a hot catalyst, causing the molecules to split apart. |
|
|
Term
| Are alkenes saturated or unsaturated? |
|
Definition
| Unsaturated. They contain fewer hydrogen atoms than alkanes with the same number of carbon atoms. |
|
|
Term
| What is the general formula for alkenes? |
|
Definition
|
|
Term
| What are the results of the bromine water test with alkenes? |
|
Definition
| They react, turning the bromine solution colourless. |
|
|
Term
|
Definition
| Small molecules that form together to create polymers. |
|
|
Term
| What is the chemical name of the polymer formed from ethene? |
|
Definition
|
|
Term
| Why are polymers formed from alkenes called 'addition polymers'? |
|
Definition
| The monomers add together to form the polymer, and no other product is formed. |
|
|
Term
| How are polymers made from alkenes used? |
|
Definition
| As plastics, e.g. bags, bottles, containers, toys. |
|
|
Term
| Why are polymers strong and flexible? |
|
Definition
| They have very long molecules that tangle together. |
|
|
Term
| Why can a thermosoftening plastic be remoulded? |
|
Definition
| Everytime it's heated, it softens. |
|
|
Term
| Why do thermosetting plastics set hard when heated? |
|
Definition
| Chemical bonds are formed between the polymer chains. |
|
|
Term
| What type of plastic would be best to make a garden hosepipe? |
|
Definition
|
|
Term
| How can we make polymers with different properties? |
|
Definition
| By changing the monomers or the reaction conditions. |
|
|
Term
| Why are polymers used widely in food packaging? |
|
Definition
| They keep food in good condition. |
|
|
Term
| How do new polymers help keep people comfortable when they are outdoors in wet weather? |
|
Definition
They can be used to create fabrics that are waterproof but are also breathable (lets gases through).
|
|
|
Term
| Give an example of a new type of polymer designed for medical use |
|
Definition
Hydrogel
Smart polymer
Shape memory polymer |
|
|
Term
| What two methods are used to extract vegetable oils? |
|
Definition
|
|
Term
| Why are vegetable oils important as foods and fuels? |
|
Definition
| They produce a lot of energy |
|
|
Term
| What is meant by an unsaturated oil? |
|
Definition
| An oil with molecules that contain carbon-carbon double bonds |
|
|
Term
| What can you use to test an oil for unsaturation? |
|
Definition
|
|
Term
| Why does food cook faster in hot oil than in boiling water? |
|
Definition
| The temperature of hot oil is higher than boiling water |
|
|
Term
| In what four ways is food cooked in oil different to food cooked in water? |
|
Definition
| Taste, colour, texture and energy content |
|
|
Term
| What type of reaction is hydrogenation? |
|
Definition
|
|
Term
| Why are oils hydrogenated? |
|
Definition
| To make them solid at room temperature |
|
|
Term
|
Definition
| By vigorously mixing/shaking together two liquids that do not usually mix together |
|
|
Term
|
Definition
| They keep the droplets suspended because different parts of their molecules are attracted to each of the liquids. |
|
|
Term
| How is an emulsion different from the liquids it is made from? |
|
Definition
| Thicker and more opaque/less transparent |
|
|
Term
| What are the four main reasons for adding substances to food? |
|
Definition
| To preserve it, to improve colour/texture/flavour |
|
|
Term
| Why are some substances given E-numbers? |
|
Definition
| To show they are permitted additives in the EU |
|
|
Term
| How could you tell from a label that a food has additives? |
|
Definition
| They would be listed in the ingredients |
|
|
Term
| What can be done to check if substances have been added to food? |
|
Definition
| They can be chemically analysed using chromatography/mass spectrometry etc. |
|
|
Term
| Why is biodiesel renewable? |
|
Definition
| It is produced from plants/crops that can be produced again |
|
|
Term
| How does biodiesel help with disposal of food waste? |
|
Definition
| Waste vegetable oil can be modified to be used as diesel fuel instead of waste |
|
|
Term
| How is biodiesel less harmful to the environment than fossil fuels? |
|
Definition
| It produces less pollution and is biodegradable |
|
|
Term
| What is the difference between the outer core and the inner core? |
|
Definition
| The outer core is a liquid, the inner core is a solid |
|
|
Term
| How did scientists think that shrinking caused mountains? |
|
Definition
| They thought the crust solidified and then the Earth cooled further causing it to shrink and the crust to wrinkle |
|
|
Term
| What are tectonic plates? |
|
Definition
| Large parts of the Earths crust and mantle (lithosphere) |
|
|
Term
| Why do tectonic plates move? |
|
Definition
| Radioactivity releases heat that causes convection currents in the mantle, which moves the plates |
|
|
Term
| What three things are likely to happen at plate boundaries? |
|
Definition
Mountains form
Earthquakes
Volcanoes |
|
|
Term
| Why were Wegener's ideas not accepted for many years? |
|
Definition
| He could not explain why continents move - he was not a geologist |
|
|
Term
| What produced much of the carbon dioxide, nitrogen and water vapour in the early atmosphere? |
|
Definition
|
|
Term
| What happened to most of the water vapour? |
|
Definition
| It condensed to form oceans |
|
|
Term
| What process produced oxygen in the atmosphere? |
|
Definition
|
|
Term
| For how long has the atmosphere been about how it is now? |
|
Definition
|
|
Term
| What is the third most abundant gas in dry air? |
|
Definition
|
|
Term
| Where did most of the carbon dioxide from the early atmosphere end up? |
|
Definition
| In sedimentary rocks and fossil fuels |
|
|
Term
| Why are noble gases so useful? |
|
Definition
|
|
Term
| What happens to most of the carbon dioxide absorbed by plants? |
|
Definition
| It returns to the atmosphere when animals respire or plants and animals die and decompose |
|
|
Term
| What is the main way (other than plants) that carbon dioxide is removed from the atmosphere? |
|
Definition
|
|
Term
| What is the main reason for the recent increase of the amount of carbon dioxide in the atmosphere? |
|
Definition
|
|
