Homologous series Flashcards
What is a homologous series?
A homologous series is a family of hydrocarbons with similar chemical properties who share the same general formula
What are the three hydrocarbons?
We will look at three hydrocarbon series: alkanes, alkenes and the cycloalkanes. Hydrocarbons are compounds that contain only hydrogen and carbon.
What are some uses for alkanes?
- Methane (natural gas) cooking, heating
- Propane used in gas cylinders for BBQ ect
- Octane used in petrol for cars
What is the general formula for alkanes?
CnH2n+2 and are insouluble in water
What is the acronym for the naming prefixes?
Monsters (Methane)
Eat (Ethane)
Pupils (Propane)
But (Butane)
Prefer (Pentane)
Hairy (Hexane)
Haggis (Heptane)
Occasionally (Octane)
What is an alkenes?
The second homologous series is the alkenes. Their names all end in –ene, for example ethene.
They contain carbon to carbon double bonds.
What is alkenes general formula?
CnH2n
What hydrocarbons decolourise bromine?
Alkenes can be used as fuels, solvents and starting materials for everyday products such as plastics and alcohol.
Are alkenes saturated or unsaturated?
The alkenes are unsaturated because they contain double donds
Are alkanes saturated or unsaturated?
The alkanes and cycloalkanes are saturated because they only contain single bonds
Does an unsaturated hydrocarbon decolourise bromine water?
An unsaturated hydrocarbon decolourises bromine water quickly. Alkanes do thus slowly
What can alkenes be used for?
- Fuels
- Solvents
- Starting materials for everyday products such as plastics and alcohol
What are the naming rules for an alkene?
Naming alkenes has the same rules as alkanes.
However, the position of the carbon to carbon double bond must be identified
E.g. 3-methylbut-1-ene
