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CARBON COMPOUND 1. Hydrocarbon – chemical compound containing carbon and hydrogen atom only. 2. Alkene – chemical compound containing carbon and hydrogen atom and at least one carbon-carbon double bond. 3. Isomers are molecules with the same molecular formula, but with different structural formula. 1. C2H4 + [O] + H2O C2H4(OH)2 2. C2H5OH + CH3COOH CH3COO C2H5 + H2O 3. C2H4 + H2O C2H5OH 4. C6H12O6 2C2H5OH + 2CO2

CH3COO C2H5 Ethyl ethanoate

CH3COOH Carboxyl -COOH

C2H5OH Hydroxyl

-OH

C2H4 Double bond between C atoms, C=C

C6H12O6

KMnO4/ H+, K2Cr2O7/ H+

C2H6

C2H5Br

C2H4(OH)2

C2H4Br2

C2H5OH

Esterification H2SO4

- CH2- CH2-

A d d i t i o n

Oxidation

Fermention

Br2

H2

KMnO4/ H+, K2Cr2O7/ H+

H2O

HX

CnH 2n+ 2 , n = 1,2 alkane CnH2n , n = 2, 3 alkene CnH 2n+ 1 OH, n = 1, 2 alcohol CnH 2n+1 COOH , n=0,1.. carboxylic acid

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Homologous

series General formula

Functional group Member , example

Alkane CnH2n + 2 ,

n = 1,2.. Single covalent bond between carbon atoms . C- C

Ethane

Alkene CnH2n , n = 2.. Double covalent bond between carbon atoms . C=C

Ethane

Alcohols CnH2n + 1 OH, n = 1,2..

Hydroxyl group / - OH Ethanol

Carboxylic acid CnH2n + 1 COOH, n = 0,1,2..

Carboxyl group , -COOH

Ethanoic acid CH3COOH

4. Your are required to prepare one namely ester by using ethanoic acid is one of the reactants. By using a namely alcohol, describe one experiment to prepare the ester. In your description include the chemical equation and observation involved. Ester: ethylethanoate Material: ethanol, etahanoic acid, water, concentrated sulphuric acid Apparatus: Boiling tube / test tube, Bunsen burner, test tube holder, beaker Procedure: 1. pour 2 cm3 of ethanol into a boiling tube / test tube 2. add 1 cm3 of ethanoic acid 3. add 2 to 4 drops of concentrated sulphuric acid 4. warm the mixture gently for about two minutes 5. pour the mixture into a beaker containing water. Observation:Sweet/ pleasant / fruity smell // insoluble in water Chemical equation : C2H5OH + CH3COOH CH3COO C2H5 + H2O

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4. Dehydration of alcohol Diagram of set up of apparatus 1. Complete and functional 2. Labels of set up of apparatus correct Procedure:

1. Place some glass wool in a boiling tube 2. Use a dropper to add propan-1-ol to wet the glass wool. 3. Clamp the boiling tube horizontally and placed unglazed porcelain chips in the mid section of the boiling tube.

4. Heat the unglazed porcelain chips strongly. 5. Then heat the glass wool gently to vaporize the propanol. 6. [Description of the chemical test to the gas collected in the test tube.]

Add 1 cm3 of bromine water and shake well.

Or, Add 1 cm3

of acidified potassium manganate(VII) solution and shake well. 7. [Observation]:

Reddish brown colour of bromine decolourised Or, Purple colour of potassium manganate(VII) solution decolourised

8. Chemical equation: C3H7OH C3H6 + H2O

water Heat

Glass wool soaked in propanol

Test tube

Unglazed porcelain

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1. Compare and differentiate between namely alkene and alkane

Alkane ( hexane ) C6H14 Alkene ( hexene ) C6H12 1 Hydrocarbon ( contain C and H atom) 2 Low melting and boiling point 3 Insoluble in water, soluble in organic solvent 4 Cannot conduct electricity 5 Density less than water 6 Completely combustion produce CO2 + H2O 7 Saturated , single covalent bond, C-C Unsaturated , contain at least one double bond

C=C 8 Unreactive – undergo substitution with

halogen in the presence of sunlight / UV ray

Reactive – undergo addition reaction ( hydrogenation, halogenations, oxidation, polymerization, with halide, steam(hydration)

9 General formula , CnH2n+2 , n = 1,2 … , CnH2n , n= 2 … 10 Identify test

1. Combustion, burn less soot flame (% of carbon per molecule is lower) Chemical tests 2. add bromine water , brown colour remains 3. add acidified KMnO4 , purple colour remains

1. More soot flame ( % of carbon per molecule is higher). 2. decolorized brown colour 3. purple colour is decolourized

5. Table shows results of latex coagulation

Procedure Observation Propanoic acid is added to latex Latex coagulates immediately Latex is left under natural conditions Latex coagulates slowly

Explain why there is a difference in these observations

Answer: 1. acid ionizes in water to produce high concentration of / a lot of hydrogen ions 2. hydrogen ions , H+ neutralize the negative charges on the protein membranes 3. the rubber particles collide and the protein membranes break 4. rubber molecules are released and combine with one another and entangle. 5. the existence of bacteria in natural conditions 6. the growth of bacteria produce / lactic acid /weak acid / low concentration of H+ ions. 7. due to the slow bacterial action, the coagulation of latex take a longer time to occur. [ monomer of natural rubber : 2 – methylbuta-1,3- diene , C5H8 / isoprene ]

Rubber particles Rubber molecules

- -

- -

- Protein membranes

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Explain how to prevent coagulation of latex 1. add ammonia solution 2. ammonia solution contains / ionized to produce hydroxide ions , OH- 3. hydroxide ions , OH- neutralized the hydrogen ions , H+ / acid produced by the

bacteria 4. the rubber particles remain negatively charged and coagulation is prevented.

6. [Paper 3] Aim : To compare the elasticity of vulcanised and unvulcanised rubber Problem statement: Does vulcanised rubber more elastic than unvulcanised rubber Hypothesis: Vulcanised rubber is more elastic than unvulcanised rubber Manipulated variable : vulcanised rubber and unvulcanised rubber Responding variable : length of rubber strip / elasticity Fixed variable : mass of weight , size of rubber Material and apparatus : retort stand, bulldog clip, meter ruler, weight, vulcanised and unvulcanised rubber Procedure:

2. hang both rubber strips to the retort stand with bulldog clip. 3. measure the initial length of both rubber strips and record. 4. hang 50 g weight to the end of each rubber using bulldog clip. 5. remove the weight and measure the length of both rubber strips and record.// 6. record all the data obtained.

Result / Data

Type of rubber Initial length , cm Length after removal of weight , cm

vulcanised unvulcanised

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[Paper 2] Conclusion:

1. Vulcanised rubber is more elastic than unvulcanised rubber due to the presence of cross-linkage of sulfur atoms between the rubber molecules. Vulcanised rubber could return to its original length after removal of the weight.

Note: 1. Rubber can be vulcanized by dipping natural rubber sheets into disulphur dichloride solution in methylbenzene or heated with sulphur.

2. Vulcanised rubber is more heat resistance due to the presence of cross-linkage of sulfur atoms increases the size of rubber molecules. Force of attraction between molecules will increase.