C10 Flashcards
Carboxylic acid
Are a homologous series of compounds that all have ‘COOH’ as a functional group
Alkenes are
Hydrocarbons which have a double bond between two of the carbon atoms in their chain
The C=C double bond means that alkenes have two
Fewer hydrogens compared with alkanes containing the same number of carbon atoms. This makes them unsaturated
The C=C double bond can open up to make a single bond,
Allowing the two carbon atoms to bond with other atoms. This makes alkenes reactive - more than alkanes
General formula for alkenes =
CnH2n
Ethene
C2H4
Propene
C3H6
Butene
C4H8
Pentene
C5H10
Alkenes burn with a
Smokeh flame
In a large amount of oxygen, alkenes
Combust completelt to produce only water and carbon dioxide
There isn’t enough oxygen in the air for complete combustion of alkenes, so when you burn rhem theycrene to undergo
Uncomplete combustion. Carbon dioxude and water still produced, but you can also get carbon and carbon monoxide which is a poisonous gas
Alkene + oxygen ———–>
Carbon + carbon monoxide + carbon dioxide + water
Incomplete combustion
Results in a smoky yellow flame and less energy being releaased compared to complete combustion of the same compound
A functional group is a
Group if atoms in a molecule that determine how that molecuke typically reacts.
All alkenes have the functional group
C=C, so they all react in similar ways. Alkenes react via addition reactions. So the carbon-carbon doubke bond will open up to leave a singke bond and a new atom is added to each carbon
Addition of hydrogen is known as hydrogenation:
Hydrogen can react with the double-bonded carbons to open up the double bond and form the eauivalent, saturated, alkane
Steam can react with alkenes to form
Alcohols
When alkenes react with steam, water us added across the doubke bond and an
Alcohol is formsd
The conversion of ethene to ethanol is one way of making ethanol
Industrially.
After the reaction has taken place, the reaction mixture is passed from the reactor into a condenser.
Ethanol and water have a higher boiling point than ethene, so both condense whilst any unreacted ethene gas is recycled back into the reactor.
The alcohol can then be purified from the mixture by fractional distillation
Explain how halogens can react with alkenes
Alkenes will also react in addition reactions with halogens such as bromine, chlorine and iodine.
The molecules formed are saturated, with the C=C carbons each becoming bonded to a halogen atom
When orange bromine water is added to a saturated compound, like an alkane
No reaction will happen and it’ll stay bright orange
If orange bromine water is added to an alkene the bromine will add
Across the double bond, making a colourless compound - becoming decolourised.
Carboxylic acids end in
Anoic acid
