Chemistry Topic 7: Organic Chemistry

23 flashcards · Other · by Marli Williams

1. What is Crude Oil?

   The remains of an ancient biomass consisting mainly of plankton that was buried in mud. It is a finite resource. It is a mixture of large number of compounds.

2. Crude oil is composed of mostly hydrocarbons.

   Think about what is extracted from Crude Oil.

3. Hydrocarbon

   A compound of only comprising of hydrogen and carbon.

4. Define Homologous Series

   Series of chemical substances with the same functional group and general formula Examples:Functional group -COOHGeneral Formula CnH2n+2

5. Alkane

   A hydrocarbon General Formula - CnH2n+2 Saturated - Only has single carbon bonds

6. Examples of Alkanes

7. How is Fractional Distillation used in terms of Crude Oil?

   The many hydrocarbons in crude oil may be separated into fractions, each of which contains molecules with a similar number of carbon atoms.

8. Uses Crude oil Fractions

   Can be processed to produce fuels and feedstock for the petrochemical industry. Produces petrol, diesel oil, kerosene, heavy fuel oil and liquefied petroleum gases Used to make solvents, lubricants, polymers, detergents

9. Why is there a vast amount of uses from crude oil?

   Due to the ability of carbon atoms to form families of similar compounds.

10. How does Fractional Distillation work?

    Fractional distillation is carried out in a fractionating column which is very hot at the bottom and cool at the top Crude oil enters the fractionating column and is heated so vapours rise Vapours of hydrocarbons with very high boiling points will immediately condense into liquid at the higher temperatures lower down and are tapped off at the bottom of the column Vapours of hydrocarbons with low boiling points will rise up the column and condense at the top to be tapped off The different fracti…

11. What are the properties of hydrocarbons dependent on?

    Size of their molecules

12. Properties of Hydrocarbons that are dependent on molecular size

    Boiling point Viscosity (resistance to flow) Flammability

13. Increase in Molecular Size causes an increase in: Boiling Point of a Hydrocarbon Viscosity And a decrease in Flammability.

    Smaller Hydrocarbons has a smaller boiling point and viscosity. They however are more flammable than larger hydrocarbons.

14. Complete combustion of Hydrocarbons

    Hydrocarbons produce carbon dioxide and water when combusted in an abundance of oxygen. Hydrocarbon + Oxygen → Carbon Dioxide + WaterExample using Methane:CH4 + 2O2 → CO2 + 2H2O

15. Cracking

    When Hydrocarbons are broken down (cracked) to produce smaller, more useful molecules. Two types of Cracking: Catalytic Cracking Steam/Thermal Cracking

16. Catalytic Cracking

    Vapourise Hydrocarbon Pass it over the catalyst aluminum oxide Thermal decomposition occurs breaking the covalent bonds

17. Steam/Thermal Cracking

    Hydrocarbon is heated at higher temperatures than catalytic cracking and mixed with steam with induces cracking.

18. Products of Cracking

    Alkanes - Saturated hydrocarbons Alkenes - Unsaturated hydrocarbons

19. How do you test a hydrocarbon whether it is an Alkane or Alkene?

    Bromine Water Test Add hydrocarbon to the orange bromine water Alkane is saturated so will not react Alkene is unsaturated so will react and change bromine water colourless This is due to the addition reaction which forms dibromo(whatever hydrocarbon used) for example dibromoethane

20. Why is cracking useful?

    High demand for fuel with small molecules like small hydrocarbons produced from cracking Modern Life is heavily depended on hydrocarbons

21. Why are Alkenes useful?

    Used to produce polymers Used as starting material for other chemicals

22. Alkene

    A hydrocarbon General Formula - CnH2n Unsaturated - Contains a single double carbon bond

23. Examples of Alkenes