17.6 The Alkenes

Question 1

What are Alkene’s made up off?

Answer 1

Hydrogen and Carbon

Question 2

What is their homologous series?

Answer 2

CnH2n

Question 3

What is their Functional group?

Answer 3

C=C

Question 4

Are Alkenes Saturated or unsaturated?

Answer 4

Unsaturated because of C=C

Question 5

What is the formula of ETHENE?

And what is the number of Carbon atoms?

Answer 5

C2H4

2 Carbons

Question 6

What is the formula for but-1-ene?

Answer 6

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

Question 7

How does the temperature vary as you add more carbon atoms to the -ene family?

Answer 7

It increases

The more Carbon atoms the higher the temperature

Question 8

What do you crack to get Alkenes?

Answer 8

Alkanes are cracked to get ALKENES.

Question 9

What conditions are needed to crack Alkanes to get ALKENES? What is also another product with the ALKENES?

Answer 9

Steam
And More than 800 degrees
Other than the Alkene the other product is Hydrogen.

Question 10

Why are AlkENES more reactive than AlkANES?

Answer 10

Because the double bond of the ENE can be easily broke down so other atoms can add on.

Question 11

You can also add hydrogen to AlkENES to get AlkANES. What are the conditions of the reaction?

Answer 11

Heat
Pressure
Catalyst

Question 12

You can from alcohols by adding steam (water) to AlkENES. What is the conditions?

Answer 12

Heat
Pressure
A catalyst

This is a reversible reaction

Question 13

What is an addition Reaction?

Answer 13

An addition reaction turns an unsaturated AlkENE into a saturated compound.
Basically from a double bond to a single bond

Question 14

What is polymerization?

Answer 14

An addition reaction undergone by AlkENES molecules where they add onto each other to form compounds with very long Carbon chains.

Question 15

What is an alkENE molecule called?

Answer 15

Monomers

Question 16

After monomers undergo polymerization, what are the long chains of Carbon called?

Answer 16

Polymers

Question 17

If polymerization is n addition reactions, what happens to the double bonds of the monomer?

Answer 17

The become saturated= single bonds.

Question 18

How do you name the product of a polymerization?

Answer 18

You put poly before the name of the AlkENE.

Ex. Polythene is the product of polymerization of ethene

Question 19

What do you use bromine water for?

Answer 19

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.

Question 20

When ethene is tested by bromine water, describe the reaction that takes place.

Answer 20

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