Organic Chemistry

How is crude oil formed

it is formed over a billion of years due to the effects of high pressures and temperatures on ancient organic matter such as plankton

What is a hydrocarbon

A compound that only contains hydrogen and carbon

What is the general formula of the homologous series of alkanes?

C_n H_2n+2

What is molecular formula

the actual number of each atom in a molecule, one molecule at a time

such as C4H10

What is displayed formula

What is structural formula

What are the first four alkanes?

Methane, ethane, propane, butane

How does fractional distillation work?

1. Heating crude oil and waiting for it to vaporise

2. the vapours of the crude oil enter the fractionating column which has a temperature gradient

3. The vapours of hydrocarbons with high boiling points condense at the bottom of the column

4. The vapours of hydrocarbons with lower boiling points rise up the column and condense at the top 

what is kerosene used for (near the middle of fractionating column)?

Jet fuel for aircrafts

what is LPG ( liquid petroleum gas) used for

Domestic heating and cooking

What is petrol used for

Car fuel

What is diesel used for?

Diesel engines

What is heavy fuel oil used for

Ships and power stations

What useful materials are made out of hydrocarbons?

solvengts, lubricants, polymers and detergents

What is the trend in boiling points for hydrocarbons?

• The bigger the hydrocarbon, the higher it's boiling point

• This is because the size of the intermolecular forces increases requiring more energy to overcome them

What is the trend in viscosity for hydrocarbons and why does it determine how useful a hydrocarbon is?

• Viscosity also increases with increasing chain length

  • This is also due to the increased intermolecular forces of attraction as molecular size increases

• Longer chain hydrocarbons would not be as useful as fuels for cars as they would be too thick and clog the engine.

• Thus they are more useful as lubricants as they are less likely to burn and function to reduce friction between moving parts

How does molecular size also affect flammability and the uses of hydrocarbons

• Smaller hydrocarbon molecules are more flammable and are easier to ignite than larger molecules

• This makes them very useful as fuels, releasing large amounts of energy when they burn

what are the products of complete combustion of hydrocarbons?

carbon dioxide and water, the carbon and hydrogen are oxidised.

When balancing a combustionequation, what order do you balance the elements

1) Carbon

2) Hydrogen

3) Oxygen

What should the temperature of a furnace used to heat a fractionating column be?

between 400 - 500

What are the condiitons needed for steam cracking?