SC22 Flashcards
(12 cards)
What are hydrocarbons made up of?
Carbon and hydrogen atoms only.
What is the general molecular formula of alkanes and alkenes?
Alkane: CₙH₂ₙ₊₂
Alkene: CₙH₂ₙ
What are alkanes?
A family of organic compounds (homologous series) whose molecules contain a hydrocarbon chain with only single covalent molecular bonds.
What are alkenes?
A family of organic compounds (homologous series) whose molecules contain a hydrocarbon chain with one carbon-carbon double bond.
What are saturated hydrocarbons?
Hydrocarbons with only single covalent molecular bonds. These hydrocarbons have the maximum number of hydrogen atoms possible per carbon atom.
What are unsaturated hydrocarbons?
Hydrocarbons with double covalent molecular bonds. The carbon-carbon bond is not ‘saturated’ because it is not bonded to the maximum number of other atoms.
What are isomers?
Molecules with the same molecular formula but different arrangements of atoms.
What is a functional group?
The atom or group of atoms in a molecule that is responsible for its main chemical reactions.
What is the test to distinguish between an alkane and an alkene?
Laboratory/Unsaturation test:
Add a small volume of bromine water (brown, formed by dissolving bromine in water) to a small amount of the alkane or alkene in a test tube and shake.
If the liquid is an alkene, the mixture changes from brown to colourless. If it is an alkane, the mixture remains brown.
What is an addition reaction?
A reaction in which reactants combine to form one larger product molecule and no other products.
Why do alkenes react with bromine in an addition reaction?
Because they have a C=C double bond.
How does bromine react with ethene?
Bromine reacts with ethene to produce a colourless liquid called 1,2-dibromoethane.
The numbers show that the two (from ‘di’) bromine atoms are attached to different carbon atoms. If they were on the same carbon atom it would be called 1,1-dibromoethane.
