Download 10.0 Carbon compound

CHEMISTRY 2012 HJH ROSSITA RADZAK
CHAPTER 11: 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 ( C = C )
3. Isomers are molecules with the same molecular formula, but with different structural formula.
Example: C4H10 – butane
n-butane
2-methylpropane
C6H12O6
Fermention
C2H4Br2
C2H6
C2H5OH
Hydroxyl
-OH
Br2
C2H5OH
C2H5Br
- CH2- CH2-
CH3COOH
Carboxyl
-COOH
Oxidation
H2
C2H4
Double bond between
C atoms, C=C
+
C2H4(OH)2
KMnO4/ H+,
K2Cr2O7/ H+
KMnO4/ H ,
K2Cr2O7/ H+
H2O
HX
A
d
d
i
t
i
o
n
Esterification
H2SO4
CH3COO C2H5
Ethyl ethanoate
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
KMnO4/H+ / K2Cr2O7/ H+
1. C2H4 + [O] + H2O
C2H4(OH)2 [ purple turns colourless] //[ orange turns green]
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CHEMISTRY 2012 HJH ROSSITA RADZAK
2. CH3COOH + C2H5OH
H 2SO4, cons
CH3COO C2H5 + H2O
H 3 PO4, 60 atm, 300 oC
3. C2H4 + H2O
4. C6H12O6
C2H5OH
Yeast
2C2H5OH + 2CO2
Homologous
series
Alkane
General formula
Functional group
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
Ethene
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
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Member , example
CHEMISTRY 2012 HJH ROSSITA RADZAK
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. Heat 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: CH3COOH + C2H5OH  CH3COO C2H5 + H2O
4. Dehydration of alcohol
Diagram of set up of apparatus
1. Complete and functional
2. Labels of set up of apparatus correct
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CHEMISTRY 2012 HJH ROSSITA RADZAK
Procedure:
a) Place some glass wool in a boiling tube
b) Use a dropper to add propan-1-ol to wet the glass wool.
c) Clamp the boiling tube horizontally and placed unglazed porcelain chips in the mid section of
the boiling tube.
d) Heat the unglazed porcelain chips strongly.
e) Then heat the glass wool gently to vaporize the propanol.
f) [Description of the chemical test to the gas collected in the test tube.]
Add 1 cm3 of bromine water and shake well.
[Observation]:
Reddish brown colour of bromine decolourised
Or,
Add 1 cm3 of acidified potassium manganate(VII) solution and shake well.
[Observation]:
Purple colour of potassium manganate(VII) solution decolourised
Chemical equation: C3H7OH à C3H6 + H2O
Industrial extraction of palm oil
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CHEMISTRY 2012 HJH ROSSITA RADZAK
5. Table shows results of latex coagulation
Procedure
Propanoic acid (weak acid) is added to latex
Latex is left under natural conditions
Protein
membranes
-
-
Observation
Latex coagulates immediately
Latex coagulates slowly
Rubber particles
-
Rubber molecules
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 takes a longer time to occur.
[Monomer of natural rubber: 2 – methylbuta-1,3- diene , C5H8 / isoprene ]
Explain how to prevent coagulation of latex
1. Add ammonia solution
2. Ammonia solution contains / ionized to produce hydroxide ions , OH3. 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 / strength of vulcanised and unvulcanised rubber
Problem statement: Does vulcanised rubber more elastic than unvulcanised rubber
Hypothesis: Vulcanised rubber is more elastic than unvulcanised rubber
Variable:
Manipulated : vulcanised rubber and unvulcanised rubber
Responding : length of rubber strip / elasticity
Fixed
: mass of weight, size of rubber
Material and apparatus:
Retort stand, bulldog clip, meter ruler, weight, vulcanised and unvulcanised rubber
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CHEMISTRY 2012 HJH ROSSITA RADZAK
Procedure:
1. Hang both rubber strips to the retort stand with bulldog clip.
2. Measure the initial length of both rubber strips and record.
3. Hang 50 g weight to the end of each rubber using bulldog clip.
4. Remove the weight and measure the length of both rubber strips and record.//
5. Record all the data obtained.
Unvulcanised rubber
Vulcanised rubber
Result / Data
Type of rubber
vulcanised
unvulcanised
Initial length , cm
Length after removal of weight , cm
Compares and contrasts the properties of vulcanized rubber
Vulcanized rubber
Harder
More elastic
Stronger
Can withstand higher temperature
Less easily oxidized
Does not become soft and sticky easily
Elasticity
Hardness
Elasticity
Tensile strength
Resistance to heat
Resistance to oxidation
Effect of organic solvent
Unvulcanised rubber
Less harder
Less elastic
Weaker
Cannot withstand higher
temperature
More easily oxidized
Become soft and sticky easily
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.
To prepare vulcanised rubber
Rubber can be vulcanized by dipping natural rubber sheets into disulphur dichloride solution
in methylbenzene or heated with sulphur.
Note:
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.
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CHEMISTRY 2012 HJH ROSSITA RADZAK
7. Compare and differentiate between namely alkene and alkane
Alkane ( hexane )
1
2
3
4
5
6
Alkene ( hexene )
Hydrocarbon ( contain C and H atom)
Low melting and boiling point
Insoluble in water, soluble in organic solvent
Cannot conduct electricity
Density less than water
Completely combustion produce CO2 + H2O
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Saturated , single covalent bond, C-C
Unsaturated , contain at least one double bond C=C
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Unreactive – undergo substitution with
halogen in the presence of sunlight / UV ray
Reactive – undergo addition reaction( hydrogenation,
halogenations, oxidation, polymerization, with halide,
steam(hydration)
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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 bromine water
3. purple colour is decolourized
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