Hydrocarbons and Crude Oil

Mixture

Two or more different substances

Fraction

A mixture of hydrocarbons with similar number of carbon atoms and similar boiling points.

Fuel

A substance that reacts with oxygen to release energy.

Feedstock

Raw materials used to supply the petrochemical industry.

Solvents

Liquids used to dissolve other substances

Lubricants

Substances that reduce friction between moving parts

Polymers

Long chain molecules made from lots of smaller molecules that join together.

Detergents

Substances that dissolve grease for cleaning things

Complete combustion

Occurs when there is a good supply of oxygen

Incomplete combustion

Occurs when there is insufficient oxygen supplied

Catalytic Cracking

A method where hydrocarbons are heated to high temperatures (around 550°C) and passed over a hot zeolite catalyst.

Steam Cracking

A method where hydrocarbons are heated to very high temperatures (around 850°C) and mixed with steam.

Unsaturated

A compound with at least one double bond (C=C).

General formula of alkenes

CH2n.

General formula of alkanes

CH2n+2.

Testing for alkenes

Bromine solution (bromine water) can be used to test for the presence of C=C double bonds.

Observation during bromine test

Orange bromine water turns colorless.

Complete combustion equation example

CH4 + 2O2 -> CO2 + 2H2O.

Incomplete combustion equation example

C3H8 + 5O2 -> 3CO + 4H2O.

First alkane

Methane (CH4).

Second alkane

Ethane (C2H6).

Third alkane

Propane (C3H8).

Fourth alkane

Butane (C4H10).

First alkene

Ethene (C2H4).

Second alkene

Propene (C3H6).

Third alkene

Butene (C4H8).

Incomplete combustion

Occurs when there is not enough oxygen present.

Harmful products of incomplete combustion

Carbon (soot) and carbon monoxide.

Crude oil

A mixture of hydrocarbons (mainly alkanes) formed from plankton from millions of years ago.

Fractional distillation

A process used to separate crude oil into different fractions.

Fraction

A group of similar length chain hydrocarbons.

Boiling point

The temperature at which a substance changes from a liquid to a gas.

Methods for cracking long chain alkanes

1. Vaporise alkane at a very high temperature and pass over a catalyst. 2) Vaporise alkane at high pressure and a high temperature and react with steam.

Bromine reaction with ethene

Bromine (Br2) reacts with ethene to form a product that changes color.

Color change when bromine reacts with alkenes

Orange to colourless.

Viscosity

A measure of how thick or 'gloopy' a liquid is; viscous liquids aren't very runny.

Correlation between chain length and boiling point

The more carbon atoms in the chain

Correlation between chain length and flammability

The longer the chain

Refinery gas

Used for bottled gas

Gasoline (Petrol)

Fuel for cars.

Naphtha

Chemical feedstock.

Kerosene

Aircraft fuel.

Diesel oil

Fuel for lorries

Fuel oil

Used for heating homes and larger buildings.

Residue

Bitumen for flat roofs and road surfaces.

Crude oil source

Remains of microscopic organisms (mainly plankton) that died and were buried in mud millions of years ago.

Fractional distillation process

1. Heat the crude oil until most of it vaporises and pump it into the fractionating column. 2) The column is hotter at the bottom and cools at the top. 3) Gases rise up the column. 4) The gases cool and condense at different temperatures (their boiling points). 5) Shorter chain hydrocarbons have lower boiling points

Most flammable fraction

Refinery gas.

Why smoking is not allowed at petrol stations

Petrol has a short chain length