| 3 Properties of Alkanes (& Structure)? | - Form a homologous series
- Have similar chemical properties
- Are saturated (C-C single bonds)
STRUCTURES(CnH2n+2):
- Methane: CH4
- Ethane: C2H6
- Propane: C3H8
- Butane: C4H10 |
| How does Fractional Distillation Work? | Seperates crude oil into simpler more useful mixtures. Works because different hydrocarbons have different boiling points:
1) heated crude oil enters a tall fractionating column, which is hot at the bottom and gets cooler towards the top
2) vapours from the oil rise through the column
3) vapours condense when they become cool enough
4) liquids are led out of the column at different heights |
| In/complete Combustion of Hydrocarbon Fuels | Complete - good oxygen supply, exothermic, CO2 and water produced, max amount of energy is given out (Bunsen burner hole fully open)
Incomplete - Poor oxygen supply. water, carbon monoxide & carbon produced, less energy released than complete combustion (fully closed Bunsen burner hole) |
| Common properties in a Homologous Series | - Same general formula
- differ by CH2 in molecular formulae from neighbouring compounds
- Show gradual variation in physical properties (boiling points)
- Similar chemical properties |
| Compare Small & Big hydrocarbon molecules | Small hydrocarbon molecules:
- are very volatile
- flow easily
- ignite easily as they have weak intermolecular forces, therefore they have low boiling points
- They do not condense, but leave the column as gases
OPPOSITE FOR BIG HYDROCARBONS |
| Definition & Uses of Crude Oil | 1) Complex mixture of hydrocarbons
2) A finite resource found in earth's crust
3) It's the remains of organisms that lived and died millions of years ago - mainly plankton which was buried in mud
USES:
- Fuels like petrol, diesel, kerosene, heavy fuel oil & liquefied petroleum gases
- Feedstock for the petrochemical industry
- Solvents
- Lubricants
- Detergents |
| The 6 Fractions and Their Uses? | (25°C - top)
1) Liquefied Petroleum Gases - fuel for heating/cooking
2) Petrol - Car fuel
3) Kerosene - Aircraft fuel
4) Diesel - Car/train fuel
5) Heavy Fuel Oil - Ship/power station fuel
6) Bitumen - for roads and roofs
(350°C - bottom) |
| 2 Types of Cracking | Alkane -> alkane(CnH2n+2) + alkene (CnH2n)
CATALYCTIC CRACKING: uses a temperature of approximately 550°C and a catalyst (zeolite, which contains aluminium oxide and silicon oxide)
STEAM CRACKING: uses a higher temperature of over 800°C, no catalyst |
