17.6 The Alkenes Flashcards
What are Alkene’s made up off?
Hydrogen and Carbon
What is their homologous series?
CnH2n
What is their Functional group?
C=C
Are Alkenes Saturated or unsaturated?
Unsaturated because of C=C
What is the formula of ETHENE?
And what is the number of Carbon atoms?
C2H4
2 Carbons
What is the formula for but-1-ene?
C4H8
The number just indicates where the C=C double bond is present.
If # is 1 , that means the C=C bond in between the 1st and 2nd CARBON ATOMS.
If # is 2 that means it’s present between 2nd and 3rd
How does the temperature vary as you add more carbon atoms to the -ene family?
It increases
The more Carbon atoms the higher the temperature
What do you crack to get Alkenes?
Alkanes are cracked to get ALKENES.
What conditions are needed to crack Alkanes to get ALKENES? What is also another product with the ALKENES?
Steam
And More than 800 degrees
Other than the Alkene the other product is Hydrogen.
Why are AlkENES more reactive than AlkANES?
Because the double bond of the ENE can be easily broke down so other atoms can add on.
You can also add hydrogen to AlkENES to get AlkANES. What are the conditions of the reaction?
Heat
Pressure
Catalyst
You can from alcohols by adding steam (water) to AlkENES. What is the conditions?
Heat
Pressure
A catalyst
This is a reversible reaction
What is an addition Reaction?
An addition reaction turns an unsaturated AlkENE into a saturated compound.
Basically from a double bond to a single bond
What is polymerization?
An addition reaction undergone by AlkENES molecules where they add onto each other to form compounds with very long Carbon chains.
What is an alkENE molecule called?
Monomers
After monomers undergo polymerization, what are the long chains of Carbon called?
Polymers
If polymerization is n addition reactions, what happens to the double bonds of the monomer?
The become saturated= single bonds.
How do you name the product of a polymerization?
You put poly before the name of the AlkENE.
Ex. Polythene is the product of polymerization of ethene
What do you use bromine water for?
To test whether a hydrocarbon is unsaturated.
If the hydrocarbon = saturated = no colour change of bromine water which means no reaction occurred.
If hydrocarbon =unsaturated = COLOUR change = COLOURLESS which means A reaction has occurred.
When ethene is tested by bromine water, describe the reaction that takes place.
The double C=C bonds break and the Br2 (bromine molecules) bond with the Carbons. The product is Dibromoethane.
The di = 2 bromine
The bromo = for bromin
EthANE = since it is saturated (single bond) of 4 hydrogen’s and 2 Carbons which is EthANE
