Hertswood Academy Gcse Chemistry C1 4 Crude Oil And Fuels

Front 1

1. What is a mixture?

Back 1

• A mixture is something made up of 2 or more substances that are not chemically bonded together and can be separated.

Front 2

2. Name three separation techniques

Back 2

• Chromatography

•Filtration

•Evaporation

•Distillation

Front 3

3. What separation technique would you use to separate 2 substances that have different boiling points?

Back 3

• Distillation

Front 4

4. What is crude oil?

Back 4

• Crude oil is a mixture of compounds known as hydrocarbons.

Front 5

5. Alkanes are found in crude oil. What are alkanes?

Back 5

• Saturated hydrocarbons

Front 6

6. What two elements are present in hydrocarbons?

Back 6

• Hydrogen and Carbon

Front 7

7. What is the general formula for alkanes?

Back 7

• CnH2n+2

Front 8

8. When drawing displayed formulas what do the lines between the atoms represent?

Back 8

• The lines between atoms represent bonds.

Front 9

9. How are the many hydrocarbons in crude oil separated into fractions by fractional distillation?

Back 9

• Crude oil is heated vaporised and fed in at the bottom of the fractionating column

• The column is hotter at the bottom and cooler at the top

• The fractions are separated by their different boiling points

• Hydrocarbons that have lower boiling points are collected near the top of the fractionating column and hydrocarbons with higher boiling points are collected near the bottom of the fractionating column

• The gases condense when they reach the temperature of their boiling points

• The different fractions are collected as liquids at different levels of the fractionating column.

Front 10

10. What is meant by viscosity?

Back 10

• Viscosity is how easily a liquid can flow.

Front 11

11. How does the size of a molecule affect the viscosity of a hydrocarbon?

Back 11

• Shorter chained hydrocarbons have a low viscosity (runny) and longer chained hydrocarbons have a high viscosity (thick).

Front 12

12. What is meant by volatility?

Back 12

• Volatility is the tendency for a liquid to turn into a gas

Front 13

13. How does the size of a molecule affect the volatility of a hydrocarbon?

Back 13

• Shorter chained hydrocarbons are very volatile and longer chained hydrocarbons are not volatile.

Front 14

14. What is meant by flammability?

Back 14

• Flammability is how easily something can burn

Front 15

15. How does the size of a molecule affect the flammability of a hydrocarbon?

Back 15

• Shorter chained hydrocarbons have high flammability therefore burn easily

• Longer chained hydrocarbons have a low flammability and therefore do not burn very easily.

Front 16

16. What length hydrocarbons are the most useful as fuels and what do they release when they burn?

Back 16

• Short chained hydrocarbons are very useful as fuels and release energy when burned.

Front 17

17. What does combustion mean?

Back 17

• Combustion is the process of burning something.

Front 18

18. What is complete combustion?

Back 18

• When something burns in plenty of oxygen.

Front 19

19. What is incomplete combustion?

Back 19

• When something burns in insufficient oxygen therefore the fuel cannot react completely.

Front 20

20. What is the word equation for the complete combustion of a hydrocarbon and the incomplete combustion of propane?

Back 20

• hydrocarbon + oxygen → carbon dioxide + water (complete)

• hydrocarbon + oxygen → carbon monoxide + carbon + water (incomplete)

Front 21

21. What is the balanced symbol equation for the complete combustion of propane?

Back 21

• C3H8 + 5O2 → 3CO2 +4H2O

Front 22

22. What is the balanced symbol equation for the incomplete combustion of ethane?

Back 22

• C2H6 +2 2O → CO + C + 3H2O

Front 23

23. Apart from carbon dioxide water and carbon monoxide; what other products can be made from combustion?

Back 23

• Sulphur dioxide

• Oxides of nitrogen

• solid particles called particulates.

Front 24

24. What environmental problems are caused by sulphur dioxide/nitrogen oxides and particulates?

Back 24

• Sulphur can react with oxygen in the air fuels are burned forming sulphur dioxide gas. Sulphur dioxide is acidic and can cause acid rain

• Nitrogen oxides are formed in a car engine and are made when nitrogen and oxygen react together at a high temperature. They can trigger people’s asthma and also cause acid rain

• Particulates travel into the upper atmosphere reflecting sunlight back into space causing global dimming

Front 25

25. How can the problems caused by impurities be reduced?

Back 25

• Removing sulphur from the fuel before combustion and removing the waste gases produced after combustion.

Front 26

26. What is a biofuel?

Back 26

• A fuel that is made from plant or animal products.

Front 27

27. What are the benefits and draw backs of using ethanol as a fuel?

Back 27

• Benefits: Ethanol is made by fermenting sugar so is therefore renewable and saves our crude oil supplies.Sugar cane crops will absorb carbon dioxide during photosynthesis.

• Drawbacks: Large amount of land is required to grow crops.

Front 28

28. What are the benefits and draw backs of using hydrogen as a fuel?

Back 28

• Benefits: Hydrogen burns with a clean flame as there is no carbon in the fuel• No pollutants made when hydrogen burns.• Water is a huge natural source of hydrogen (obtained by electrolysis)

• Drawbacks: When hydrogen is mixed with air and ignited is it very explosive.• Hydrogen is a gas and takes up larger volumes than liquid so there are issues with storage.