Hydrocarbons Flashcards
What is the general formula for alkanes?
CnH2n+2 (Check google if unsure)
Name the first four alkanes and write their molecular
formulae
Methane - CH4
Ethane - C2H6
Propane - C3H8
Butane - C4H10
What type of bond are formed between carbon and
hydrogen atoms in alkanes?
Covalent bonds
What is the displayed formula of ethane?
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Page 74 C2H6
Why are alkanes saturated hydrocarbons?
Saturated - all C-C bonds are single
bonds.
Hydrocarbon - only contain carbon and
hydrogen atoms.
What is the general formula for alkenes?
CnH2n (Check google if unsure)
Name the first four alkenes and write their molecular
formulae
Ethene - C2H4
Propene - C3H6
Butene - C4H8
Pentene - C5H10
Why are alkenes unsaturated hydrocarbons?
They are compounds made up of only
carbon and hydrogen atoms and they
contain double carbon bonds, C=C.
What is a functional group?
The group of atoms responsible for the main chemical properties of a compound.
What functional group do alkenes contain?
C=C double bond
What is the difference between but-1-ene and
but-2-ene?
But-1-ene and but-2-ene are both alkenes with 4
carbons but the C=C bond is found between different
carbons in the chain. In but-1-ene, the double bond
is between the first and second carbon whereas in
but-2-ene, it is between the second and third carbon
in the chain.
What is the word and balanced symbol equation for the addition reaction between ethene and bromine?
Ethene + Bromine → 1,2-dibromoethane
C2H4 + Br2 → C2H4Br2
Draw the displayed formula of 1,2-dibromoethane
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Page 92 C2H4BR2
How can bromine water be used to distinguish between alkanes and alkenes?
When bromine water is added to an alkane, the solution remains orange.
When bromine water is added to an alkene, the solution changes from orange to colourless.
Why do alkenes decolourise bromine water?
Alkenes are unsaturated. The double
bond allows alkenes to react with
bromine to form a bromoalkane.
