What is a covalent bond?
A shared pair of electrons
Explain why small molecules have low melting and boiling points.
Small molecules have weak intermolecular forces between molecules that require very little energy to overcome
Explain why fossil fuels are said to be non-renewable.
They are being used faster than they are replaced
Describe how crude oil is formed.
Plankton died, were buried under sediment and compressed via heat and pressure over millions of years
Define hydrocarbon.
A compound made up of ONLY hydrogen and carbon
What is the general formula of alkanes?
CnH2n+2
What are the names of the first four alkanes?
Methane, ethane, propane, butane
State the properties of long-chain hydrocarbons.
High boiling point, low volatility, high viscosity, not very flammable
Name the process used to separate crude oil.
Fractional distillation
Name the products of complete combustion.
Carbon dioxide and water
When does incomplete combustion occur?
Limited supply of oxygen
What is cracking?
A process where longer chain alkanes are broken down (cracked) into smaller, more useful ones
Name the conditions needed for catalytic cracking.
Catalyst and high temperature
Alkenes are described as unsaturated hydrocarbons. Define unsaturated.
Contain at least one C=C double bond
Describe the test for alkenes, including the positive result.
Add bromine water, bromine water turns from orange to colourless (decolourises)
