DF - Addition reactions of alkenes Flashcards
Which are more reactive, single bonds or double bonds?
double
Why are double bonds more reactive than single bonds?
Because there’s more electron density in double bonds.
What do alkenes join up to form?
Addition polymers.
What is an addition polymer?
Alkenes joined together.
How do alkenes join together to form addition polymers?
The double bonds can open up and join together to make long chains called polymers.
What are alkenes examples of when they are in a polymer?
Monomers.
What is polyethene made by?
Addition polymerisation of ethene.
What does adding hydrogen to C=C bonds produce?
Alkanes.
Ethene will react with hydrogen to produce…
Ethane
What conditions need to be present for ethene to react with hydrogen to produce ethane?
A catalyst - either a nickel catalyst and a temperature of 150 degrees celsius and a high pressure or a platinum catalyst at room temperature.
What do you use to test for C=C bonds?
bromine water
How do you test for C=C bonds?
Shake an alkene with orange bromine water, the solution quickly decolourises if C=C bonds are present.
What is the use of bromine water a test for?
Unsaturation (the presence of double or triple carbon-carbon bonds).
What is bromine reacting with an alkene an example of?
Electrophilic addition.
Give an example of electrophilic addition
bromine reacting with an alkene
What are electrophiles?
Electron-pair acceptors (such as positively charged ions and polar molecules). They are attracted to areas where there are lots of electrons about.
What is electrophilic addition?
The double bonds open up and atoms are added to the carbon atoms because the double bond has got plenty of electrons and is easily attacked by electrophiles.
What do electrophilic addition reactions happen to?
Alkenes
What can a double bond be described as being?
nucleophilic
What does it mean that a double bond is nucleophilic?
It’s attracted to places that don’t have enough electrons.
What do electrophilic addition reactions do to the double bond?
Open it up.
What does a curly arrow mean?
Shows the movement of a pair of electrons. It starts from an electron pair - a covalent bond or a lone pair.
What is a carbocation?
An organic ion containing a positively charged carbon atom.
What do alkenes undergo addition with?
Halides and hydrogen halides.
