8984468
Descrição
FlashCards por Natalia Cliff, atualizado more than 1 year ago
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Criado por Natalia Cliff
aproximadamente 7 anos atrás
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| Questão | Responda |
| What is crude oil? | A mixture of hydrocarbons (mainly saturated hydrocarbons called alkanes) |
| What is a mixture | two or more elements or compounds that are not chemically bonded so the chemical properties of each substance of the mixture remains unchanged and so it can be separated physically |
| What is the general formula and structure of alkanes? |
CnH2n+2
Image:
Ethane (image/png)
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| Describe the process of fractional distillation | -Heat so most vaporise -put them into the column -Vapours rise and cool - condense off at their separate boiling points -Low boiling points at the top -Gathered at their boiling points and carried away in pipes |
| What are the properties of long hydrocarbons? and short hydrocarbons? | Long hydrocarbons: -Viscous -High boiling point -Not very flammable Short hydrocarbons are vice versa |
| What do most fuels (including coal) contain? | Most fuels contain carbon, hydrogen and sometimes sulfur |
| What happens during combustion? | The carbon and hydrogen get oxidised which releases energy |
| What gases are released by combustion? What do these gases cause? | -CO2 causes global warming -Sulphur dioxide causes acid rain -Oxides of nitrogen cause acid rain -Carbon monoxide is a toxic gas -Particulates cause global dimming |
| When are oxides of nitrogen and particulates formed? | -Oxides of nitrogen are formed at high temperatures -Particulates are formed by incomplete combustion of carbon (e.g. soot) |
| When is sulphur removed? | -Can be removed before fuel is burnt, e.g. in cars -Can also be removed from the waste gases after combustion, e.g. in power stations |
| What are biofuels made from? | plant material |
| Give two examples of biofuels | methane and ethanol |
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