7. Organic chemistry Flashcards
What is the general formula for alkanes
CnH2n+2 eg C4H10
Order of alkane molecular formula
Methane CH4
Ethane C2H6
Propane C3H8
Butane C4H10
What are hydrocarbons
Molecules that only contain hydrogen and carbon
Why are alkanes SATURATED hydrocarbons
Saturated as they only contain single bonds
Why are alkanes a homologous series
Successive molecules differ by CH2
They have similar chemical properties
They have the same general formula
Chemical test to distinguish between alkenes and alkanes
Add bromine
Alkene will turn it from orange to colourless
Alkane will have no reaction
What is complete combustion
Burning in excess oxygen to form CO2 and H2O
What is incomplete combustion
Burning in limited oxygen to form CO or C and H2O
Bonding in alkenes
All single bonds except for between the 2 carbons is a double bond
Order of alkene molecules
Ethene
Propene
Butene
(No methene as it only has 1 carbon and 2 is needed to form a double bond)
Alkenes are unsaturated hydrocarbons because
they don’t only contain single bonds (they contain a double bond)
What is the general formula for alkenes
CnH2n
Why are alkenes a homologous series
Successive molecules differ by CH2
Have similar chemical properties
Have same general formula
What is a functional group
An atom/group that gives a molecule similar chemical properties and react similarly
How do alkenes become alkanes
Addition reactions - The double bond breaks and other atoms add on. Alkenes + H2 make the equivalent alkane
