Chemistry Topic 7//Alkenes//Addition Polymers Flashcards
What are Alkenes
hydrocarbons which have a C=C double bond between 2 carbon atoms
Why are alkenes unsaturated
Because alkenes have 2 fewer hydrogens than alkanes but containing same number of carbon atoms
Why are alkenes reactive
The C=C bond can open up to make a single bond allowing 2 carbon atoms to react with other atoms
What is the general formula for alkenes
CnH2n
What are the 4 alkenes and there formula
Ethene- C2H4
Propene- C3H6
Butene- C4H8
Pentene- C5H10
Describe how alkenes react when they combust in oxygen
In a large amount of oxygen, alkenes combust completely to produce water and carbon dioxide and a lot of energy
Describe how alkenes react when they combust in air
When you burn alkenes in air, they tend to undergo incomplete combustion to produce carbon dioxide, water, carbon and carbon monoxide (poisonous gas)
What does an incomplete combustion result in and what happens to the energy released
Incomplete combustion results in a smoky yellow flame and there is less energy being released
What are the three types of addition reactions with
Water
Hydrogen
Halogens
Describe what happens when an alkene reacts with hydrogen
Hydrogen can react with the double bonded carbons in the presence of catalyst to open up the double bonds and form the saturated alkane
Describe what happens when an alkene reacts with halogens
Halogens react with the double bonded carbons to open up the double bonds and form saturated alkanes
Describe what happens when orange bromine water is added to an ALKANE and ALKENE
When orange bromine water is added to an ALKANE, no reaction happens because they do not have a double carbon bond.
When orange bromine water is added to an ALKENE, the bromine will add across the double carbon bond making colourless dibro-compound so bromine is decolourised
What is a polymer
Made up of long molecules formed when lots of small molecules called monomers join together which is called polymerisation
What are addition polymers made from
Unsaturated monomers
what do the monomers in addition polymerisation contain
They contain double carbon bonds C=C