Unit 2 Hydrocarbons Flashcards
What do hydrocarbons contain
Hydrogen and carbon only
What are the three families of hydrocarbons
- Alkanes
- Alkenes
- Cycloalkanes
What is a homologous series
Family of compounds with the same general formula and similar chemical properties
What are alkanes
Hydrocarbons that all consist of carbon and hydrogen on and every carbon has 2 single covalent bonds
What is a the general formula of alkanes
Cn +H2n +2
What hydrocarbons are saturated
Alkanes and cycloalkanes are saturated
What does saturated mean
They contain carbon to carbon single bonds
What happened to alkanes in water
Nothing as alkanes are insoluble
What at alkanes commonly used for
They are commonly used a fuels in cookers/boilers, propane/butane camping gas.
Which covalent molecular substances boil which bonds are broken, the stronger covalent bonds within the molecule are the weaker intermolecular bonds between molecules
The weaker forces of attraction (intermolecular forces) between molecules
What happens to alkanes the the molecular size increases
As the molecular size increases, there is an increase in strength of the intermolecular forces (there is more of them) between the molecules so the melting point and boiling point increases
What is the structural formula used for?
To show how the atoms in a molecule are joined. You can also use the shortened structure formula.
What are isomers?
Compounds that have the same molecular formula but have a different structural formula
What is cracking used for?
It is used to take longer hydrocarbons and turn them into more useful, smaller hydrocarbons.
How is a catalyst used in cracking?
A catalyst can be used to allow the cracking to take place at a lower temperature
What hydrocarbons are unsaturated?
Alkenes are unsaturated
What does unsaturated mean
Contain a carbon to carbon double bond (C=C)
What happened when an Alkenes is in the water
Nothing as Alkenes are insoluble
How is an Alkenes made
It is obtained by cracking crude oil fractions
What are small Alkenes used to make
Polymers and alcohol
What is the general formula for Alkenes
CnH2n
Why do Alkenes have to be unsaturated
So they can undergo addition reactions across the carbon to carbon double bond
What is the chemical test for Alkenes
They decolourise in bromine water
What happens to Alkenes in bromine water
Alkenes will react with bromine water, and as such all decolourise bromine water
