Ethene Experiment(Complete)

Question 1

What is the formula for ethene?

Answer 1

C2H4.

Question 2

What is the general formula for an alkene?

Answer 2

CnH2n

Question 3

What is a functional group?

Answer 3

A group of atoms which give the homologous series its main characteristics.

Question 4

What is the functional group of ethene?

Answer 4

C=C.

Question 5

What is an isomer?

Answer 5

Same molecular formula but different structural formulae.

Question 6

Why do isomers occur?

Answer 6

Due to different positions of the double bond.

Due to branching.

Question 7

What its an unsaturated hydrocarbon?

Answer 7

Unsaturated: Contains one or more double or triple carbon to carbon bonds.
Hydrocarbon: Consists of hydrogen and carbon only.

Question 8

Describe alkenes in terms of solubility.

Answer 8

Alkenes are non-polar.
Alkenes cannot dissolve in water as water is polar and alkenes are non polar.
Alkenes are soluble in non-polar solvents , e.g Octane, benzene, cyclohexane.

Question 9

How do you produce ethene industrially?

Answer 9

By catalytic cracking of long chains alkanes.

C10H22= C2H4 + C5H12 + C3H6

Question 10

Why is catalytic cracking done in oil refineries?

Answer 10

As the separating equipment/ apparatus is there.

Raw materials are there.

Question 11

How do you produce ethene in a laboratory?

Answer 11

Dehydrating ethanol.

C2H5OH= C2H4 +H2O

Question 12

Draw a diagram showing the production of ethene.

Answer 12

Diagram in manual.

Question 13

What is the purpose of the bunsen burner?

Answer 13

To heat the aluminium oxide strongly.

Question 14

What is the purpose of aluminium oxide?

Answer 14

To act as a catalyst/ dehydrating agent.

Question 15

What is the appearance of aluminium oxide?

Answer 15

White powder.

Question 16

What is the purpose of the glass wool?

Answer 16

To hold the ethanol in place to prevent it from reaching the aluminium oxide.

Question 17

How do you collect ethene?

Answer 17

Over water as ethene is non polar and therefore cannot dissolve in water as water is polar.

Question 18

Name 3 precautions used when carrying out the ethene experiment.

Answer 18

Remove the delivery tube before heating has stopped to prevent suck- back and explosion.
Wear protective goggles to prevent glass from going into your eye.
Wear a lab coat to prevent chemicals from leaking onto your clothes.

Question 19

How is ethene formed?

Answer 19

By an elimination reaction involving ethanol.
Water is removed and a c=c double bond forms.
Dehydration reaction as water is removed.

Question 20

What are the main characteristics of ethene?

Answer 20

Non polar.
Colourless.
Sweet smell.
Burns with oxygen to form carbon dioxide and water.
Produces a yellow non smoky flame when heated.

Question 21

Give the equation of the heat of combustion of ethene.

Answer 21

C2H4 + 3O2 =2CO2 + 2H2O

Question 22

How do you prove that ethene is unsaturated?

Answer 22

Shake with bromine water- tuns from red/brown to colourless.

Shake with acidified KMNO4- turns from pink to colourless.

Question 23

Give one major use of ethene.

Answer 23

Ripening fruit or making polythene.