c11 tahap 3 rusli
TRANSCRIPT
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
11 CARBON COMPOUNDS
11.1 ORGANIC COMPOUNDS
Carbon compounds are compounds that contain the carbon element.
HYDROCARBON
Hydrocarbons are organic compounds that contain ……..…………., C
and……………….., H.
The main source of hydrocarbons are ………………..gas and ……………………. It is formed as a result of decomposition of plants and animals that died million years ago.
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
37
Carbon compounds
Organic compoundscarbon compounds that are obtained from living things (plants and animals) such as sugar/glucose (C6H12O6), starch, protein, vitamin, enzym etc.
Inorganic compoundscarbon compounds that are usually do not contain carbon to carbon bonds such as carbon monoxide (CO), carbon dioxide (CO2), calsium carbonate (CaCO3) etc.
Hydrocarbons Non-Hydrocarbons
Hydrocarbons
Saturated Hydrocarbonscontain only …………….covalent bonds between ………atoms. C - C
Unsaturated Hydrocarbonscontain at least one ……………or ………..covalent bond between carbon atoms. C = C C = C
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
11.2 ALKANES
1 Alkanes are ……………….hydrocarbons.
2 The general formula of alkanes:……………………………………
3 Each carbon atom is bonded to four other atoms(carbon or hydrogen atoms) by
…………..covalent bonds.
4 Naming of Alkanes (IUPAC)
The names of straight chain alkanes (all the carbon atoms are joined in a continuous chain) are made up of two component parts :
Stem / root
indicates the number of carbon atoms in the longest continuous carbon chain.The names of stems for the first ten straight alkanes are :
Number of carbon atom
1 2 3 4 5 6 7 8 9 10
Stem Meth Eth Prop But Pent Hex Hept Oct Non Dec
Suffix / ending
indicates the family of the compound. For alkane, the suffix is ‘ane’ because it belongs to the alkane group.
Number of carbon atoms,
n
Name of alkane
Molecular Formula, CnH2n+2
Structural Formula
1 Methane CH4
2 Ethane C2H6
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
38
– C –
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
Number of carbon atoms,
n
Name of alkane
Molecular Formula, CnH2n+2
Structural Formula
3 Propane C3H8
4 Butane C4H10
5 Pentane C5H12
6 Hexane
7 Heptane
8 Octane
9 Nonane
5 Physical properties of alkanes
Alkanes are covalent compound which consist of molecules. These molecules are held together by …………………intermolecular forces.
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
39
Covalent bond (strong covalent bond) Intermolecular force
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
Alkanes have physical properties similar to other covalent compounds.
Physical property Explaination
1 Low ……………………points
The molecules are held together by …………..intermolecular forces. ……………..amount of heat required to overcome the forces.
2
……………….in water but ……………….in organic solvents (ether, benzene, tetrachloromethene)
3…………………conduct electricity
4 ……………dense than water ……………on top of water
Name of members
Molecular Formula
Molar mass/ g mol-1
Melting and Boiling point
Density
Methane CH4 16Ethane C2H6 30PropaneButane C4H10 58PentaneHexane 86Heptane
6 Chemical properties of alkanes
Alkanes are saturated hydrocarbon (have single covalent bonds, C – C and C –H) Hence, alkanes are generally chemically………………………..
Combustion
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
40
………..
Gradually
………..
Gradually
CH2
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
Alkanes undergo complete combustion in the presence of excess oxygen to form carbon dioxide and water .
Alkane + oxygen → carbon dioxide + water
Step 1 : Balance C → Step 2 : Balance H → Step 3 : Balance O
(i) CH4 + 2O2 → CO2 + 2H2O
(ii) C2H6 + O2 → 2CO2 + 3H2O ..X 2
2C2H6 + 7O2 → 4CO2 + 6H2O
Balance the equations :
(iii) C3H8 + O2 → CO2 + H2O
(iv) C4H10 + O2 → CO2 + H2O
(v) C5H12 + O2 → CO2 + H2O
Alkanes undergo incomplete combustion when there is insufficient oxygen to form carbon dioxide gas, carbon monoxide gas carbon (in the form of soot) and water.
Substitution Reaction
Alkanes react with halogens (Cl2 and Br2) in the presence of ……………..or ………………..light
In this reaction, each hydrogen atoms in the alkane molecule are substituted one by one by halogen atoms.
Example :When methane reacts with chlorine gas in the presence of ultraviolet light, a variety of substituted products are formed :
Step 1
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
41
UV
UV
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
CH4 + Cl2 CH3Cl + HCl
(methane) (chloromethane)
Step 2
CH3Cl + Cl2 CH2Cl2 + HCl
(dichloromethane)
Step 3
CH2Cl2 + Cl2 CHCl3 + HCl
(trichloromethane)
Step 4
CHCl3 + Cl2 CHCl4 + HCl
( tetrachloromethane)
11.3 ALKENES
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
42
UV
UV
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
1 Alkenes are unsaturated hydrocarbons.
2 General formula : …………………………………………
3 The functional group of the alkene ………………………………
Example : ethene
4 Naming of Alkenes (straight chain) (IUPAC)
(i) Determine the longest carbon chain containing double bond, give the stem name according to the number of carbon atoms ; eth, prop, but, pent, hex, hept, oct, non and dec.
(ii) Add the suffix “ene” at the end of the name.
(iii) Number the carbon atoms from the end nearer to the double bond and give the double bond the smaller number.
(iv) The first member of alkenes has two carbon atoms in a molecule
because : …………………………………………………………………..
Number of carbon atoms,
n
Name of alkaneMolecular Formula,
CnH2n
Structural Formula
2 Ethene C2H4
3 Propene C3H6
4 But-1-ene
5 Pent-1-ene
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
43
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
Number of carbon atoms,
n
Name of alkaneMolecular Formula,
CnH2n
Structural Formula
6 Hex-1-ene
7 Hept-1-ene
8 Oct-1-ene
5 Physical properties of alkenes
Physical properties of Alkenes are similar to alkanes.
i …………………….melting and boiling points,
ii ……………………in water but ………………….in organic solvents,
iii …………………….conduct electricity and Less dense than water
6 Chemical properties of alkenes
Alkenes are chemically more ……………….than alkanes because of the existence of ……………….covalent bond between two carbon atoms.
Almost all of the chemical reactions of alkene occur at the double bond.
Combustion Reaction
Alkene burns completely in the excess oxygen to produce carbon dioxide and water.
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
44
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
Alkene + oxygen → carbon dioxide + water
Example : C2H4 + 3O2 → 2CO2 + 2H2O
Balance the following equations :
(i) C3H6 + O2 → CO2 + H2O
(ii) C4H8 + O2 → CO2 + H2O
(iii) C5H10 + O2 → CO2 + H2O
Alkene burns incompletely in limited supply of oxygen to form carbon dioxide, carbon monoxide, carbon (in the form of soot) and water.
Addition Reaction
As alkenes are unsaturated hydrocarbon, they undergo addition reaction.
An addition reaction is a reaction in which other atoms are added to each
carbon atom of the double bond, [C = C ] to form single covalent bond
product [ C-C ].
C = C + AB C C
A B (i) Addition of Hydrogen (Hydrogenation)
Alkenes react with hydrogen at ……………..C in the presence of
………………………. as a catalyst to produce……………………..
Example :
H H H H
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
45
Ni / Pt
180 C
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
H C C H + H2 H C C H
Ethene H H Ethane
(ii) Addition of Halogen (Halogenation)
Alkenes react with halogens such as chlorine and bromine at room conditions.(no catalyst or ultraviolet light needed)
Example :
H H H H
H C C H + Br2 H C C H
Ethene (bromine water) Br Br 1,2-dibromoethane
When ethene gas is passed through bromine water, brown colour of bromine water is…………………………….
This reaction is used to distiguish a saturated hydrocarbon and unsaturated hydrocarbon.
(iii) Addition of Hydrogen Halide [ HX ]
Alkenes react with hydrogen halide such as hydrogen chloride, HCl or hydrogen bromide, HBr at room temperature to form haloalkane.
Example :
C2H4 + HCl → C2H5 Cl Ethene Hydrogen chloride Chloroethane
C3H6 + HBr → Propene Hydrogen bromide ………………….
(iv) Addition of hydroxyl groups (Acidified Potassium manganate(VII), KMnO4 // Potassium dicrhoromate(VI), K2Cr2O7 solution)
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
46
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
In this reaction, two hydroxyl, -OH groups are added to the
carbon-carbon double bond in an alkene molecule.
An alkene …………………the purple solution of acidified
potassium manganate(VII) // the ……………solution of acidified
Potassium dicrhoromate(VI), K2Cr2O7 turns to……………...
This reaction is used to distiguish a saturated hydrocarbon and
unsaturated hydrocarbon.
Example :
C2H4 + H2O + [O] → C2H4(OH)2
Ethene Ethane-1,2-diol
Complete the following equation :
C3H6 + H2O + [O] →
H H H C = C H + H2O + [O] →
(v) Addition of Water (Hydration)
Alkenes react with water (in the form of steam) at high temperature and pressure in the presence of ……………….acid as a catalyst to produce alchohols.
Alkene + H2O Alcohol
Example :
C2H4 + H2O C2H5OH
Ethene ethanol
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
47
H3PO4
300 C / 60 atm
H3PO4
300 C / 60 atm
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
Complete the following equation :
C3H6 + H2O
H H H C = C H + H2O
Addition of steam to alkene is one way to manufacture alcohol in industry:
CnH2n + H2O(g) CnH2n+1OH Alkene Alcohol
Polymerisation reaction
In this reaction, small alkene molecules undergo addition reaction at a
high pressure of 1000 atm and temperature of 200 C. Thousands of
alkene molecule join together to form long chain giant molecules
called………………………………..
The small repeating units of molecules that join together to form polymer
are called ………………………….
Example : Polymerisation of ethene
Polythene Polymerisation of propene:
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
48
H3PO4
300 C / 60 atm
H3PO4
300 C / 60 atm
H H
H C C H
Ethene
H H
C C
H H
n is large number up to a few thousands
n
n
H3PO4
300 C / 60 atm
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
COMPARING PROPERTIES OF ALKANE WITH ALKENE
Alkanes Alkenes
Similar(physical properties)
……………..melting and boiling points ………………….melting and boiling points
……………..in water but ………………in organic solvents
……………..in water but ………………….in organic solvents
……………………..conduct electricity ……………………………conduct electricity
……………….dense than water …………………………dense than water
Different(chemical properties)
unreactive
Burn in air to produce ……………….flame Burn in air to produce very sooty flame
Undergo subtitution reaction Undergo ………………………reaction
…………………react with bromine………………….with bromine (brown colour of bromine ……………………….
……………..react with acidified potassium manganate(VII) solution
…………………..with acidified potassium manganate(VII) solution (purple colour
……………………)
7 HOMOLOGOUS SERIES
Homologous series are groups of carbon compounds that have the following general characteristics :
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
49
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
(a) Members having the same ………………………… properties because they
have the same ………………………. (group that takes part in a reaction).
(b) Members of the series can be represented by a …………………………
formula.
(c) Members of the series can be prepared by the …………………………
(d) Two consecutive members in the series have a difference in relative atomic
mass of 14, a difference of CH2.
(e) Members of the series have physical properties that …………………………
gradually as the number of carbon atoms in a molecule
…………………………
1. Example of homologous series :
Homologous Series
General FormulaFunctional
groupExample of members
AlkaneCnH2n+2
n = 1, 2, 3, …
C – CSingle bond
Propane
Alkene
AlcoholCnH2n+1 OH
n = 1, 2, 3, …
-OHHydroxyl
group
Carboxylic acidCnH2n+1 COOH
n = 0, 1, 2, 3, …
-COOHCarboxyl
group
Ester
CnH2n+1 COO Cn’H2n’+1
n = 0, 1, 2, 3, …n’ = 1, 2, 3,…
-COOC-
8 ISOMERISM
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
50
Number of carbon in the longest chain
(4 carbon atoms)
Homologous series
(alkene)
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
Method of writing the Name of organic compound using IUPAC nomenclature
Prefix
(Branch)
Stem
( number of carbon atoms in the longest carbon
chain)*
Suffix
(functional group / homologous series)
* for alkenes, the smallest number is given to the carbon with the double bond.
Example :
2,3-dimethylbut-1-ene
(a) Name the following compounds.
(i) (ii)
………………………………… …………………………………
(iii) (iv)
Name : ……………………………… Name : …………………..……
(v) (vi)
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
51
SuffixStem
Branch
Prefix
CH3
H3C CH CH2 CH2 CH3
H3C CH CH2 CH2 CH3
CH2 CH3
CH3
H3C CH = CH CH CH3
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
Name : …………………………… Name : ……………………………
(b) Draw the structural formula for the following molecules :
(i) 2,-methylhexane (ii) 2,4-dimethylpentane
(iii) 3-methylpent-2-ene (iv) 2,3-dimethylhex-2-ene
Isomerism is phenomenon where a compound has the ………….
molecular formula but ……………………..structural formulae.
Molecular formula shows the type and number of atoms in a molecular compound.
Structural formula shows the type and number of atoms for each element, and how the atoms are ………………..to one another in a compound.
Molecular Formula
Structural Formula & IUPAC nameNumber of
IsomersC4H10
Butane
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
52
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
…………………….
C5H12
C4H8
C5H10
11.5 ALCOHOL
1 Alcohols are organic compounds that contain……………., ………………….and
………………………….atoms.
2 The general formula for alcohol is :……………………………………………………
3 Functional group :…………………………………………………………..
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
53
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
4 Naming alcohol using IUPAC nomenclature :
Determine the number of carbon atoms in the longest carbon chain which contains the hydroxyl group ( –OH ) obtain the name of alkane with the same number of carbon atom as alcohol.
Replace the ending “e” from the name of alkane with “ol”
Example :
Methane MethanolEthane EthanolPropane ?Butane ?
Number the carbon atom in the longest carbon chain which is joined to the hydroxyl group -OH with the smallest number the number is placed in front of the “ ol ” to indicate which carbon atom the hydroxyl group is attached to.
Example :
Butan-2-ol
Name : ………………….. Name : ………………….
Name : ………………….. Name : ………………….. Name : …………………..
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
54
4 carbon atoms -OH
-OH at the 2nd C
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
5 Isomerism in alcohol :
Isomers are molecules that have …………. molecular formula but …………………structural formula.
Methanol and ethanol do not have isomers. Isomerism in alcohol begins with propanol
Complete the following table :
Name of alcohol
Molecular Formula
Structural Formula & IUPAC name
Number of isomers
Propanol C3H7OH 2
Butanol 4
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
55
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
6 Preparation of Ethanol
Two methods of preparation of Ethanol
(i) Preparation of ethanol, C2H5OH in the laboratory ( Fermentation of glucose)
7 Physical properties of alcohol
Alcohols with one to eleven carbon atoms exist as……………………..
Methanol, ethanol and propanol mix with water in all……………………... Solubility in water decreases with increasing of molecular size.
Physical properties of ethanol, C2H5OH :
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
56
Preparation of Ethanol
In the laboratory
Process : ………………………
………………..is a process in which microorganism such as yeast act on
…………………..(sugar or starch) to produce ………………..and …………………
C6H12O6 → 2C2H5OH + 2CO2 Glucose Ethanol
In industry :
Process : ………………………………
Alkene is reacted with …………… at temperature; ……….. oC and pressure; …………atm in presence of
……………………………… as a catalyst.
C2H4 + H2O → C2 H5OHEthene steam ethanol
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
Colour : ………………………..
mixes with water in all ………………..
………dense than water
boiling point is ………. ....... at 1 atm.
8 Chemical properties of ethanol, C2H5OH
(a) Combustion of ethanol
(i) Ethanol burns in air to produce …………..and…………………...
(ii) Ethanol burns readily with a …………flame and …………….producing soot.
C2H5OH + 3O2 → 2CO2 + 3H2O
(ii) Combustion of ethanol releases …………….amount of heat (ethanol is suitable for use as a fuel)
Balance the following equations :
2C3H7OH + 9O2 → 6CO2 + 8H2O
C4H9OH + O2 → CO2 + H2O
C5H11OH + O2 → CO2 + H2O
C6H13OH + 9O2 → 6CO2 + 7H2O
(b) Oxidation of ethanol
(i) Ethanol is oxidised by an oxidising agent such
as……………………………………………………, KMnO4
or……………………………………………………., ………….7 solution
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
57
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
produce ………………………………….
Example :
C2H5OH + 2[O] → CH3COOH + H2O
Ethanol Ethanoic acid water
or
H H H
H C C H + 2[O] → H C C + H2O
H OH H
Complete the following equations :
C3H7OH + 2[O] → C2H5 COOH + H2O
or
CH3CH2 CH2OH + 2[O] → ……………………… + H2O
Propanol propanoic acid
or
H H H
H C C C H + 2[O] → + H2O
H H OH
……………………..
(c) Dehydration of ethanol
(i) Dehydration of an alcohol involves the removal of ……………molecule from each of alcohol molecule.
(ii) Water molecule from the alcohol molecule is removed by a
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
58
O
OH
From oxidising agent
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
dehydration agents such as ……………………/ ………………………/
concentrated ……………..acid / concentrated phosphoric acid.
(iii) There are two ways to carry out the dehydration of ethanol in the laboratory :1 Hot vapour of ethanol is passed over a heated catalyst such as
porcelain chips /aluminium oxide.1 Ethanol is heated under reflux with excess of concentrated
sulphuric acid / concentrated phosphoric acid.
Draw a labelled diagram to show the set-up of apparatus to carry out the dehydration of ethanol.
(iv) Dehydration of ethanol produces ………………and…………………...
Equation for the reaction :
H H H H porcelain
H C C H H C C H + H2O ∆
H OH
or
C2H5OH → C2H4 + H2O Ethanol Ethene
Complete the following equations :
(a) C3H7OH → + H2O
……….. …………
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
59
∆
∆
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
(b) → + H2O
Butanol …………
9 Uses of alcohol
Uses Example/explanation1 As a fuel
releases a …………of heat energy
2 As a solvent
3 Antiseptic
4
11.6 CARBOXYLIC ACID [ ORGANIC ACID ]
1 CARBOXYLIC ACID Consists of elements :…………., C ; ……………., H ;
and…………………, O.
2 The general formula of the carboxylic acid is :………………………………………
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
60
∆
STARCH
GLUCOSE
……………. ETHENE PETROLEUM
Combustion in excess oxygen
Oxidationby an oxidising agent
Dehydrationby a dehydrating agent
…………………. and
………………….
Fermentation
Hydration
…………………. and
………………….
…………………. and
………………….
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
3 Functional group is the …………………group :
4 For straight chain carboxylic acid molecules, the name ends with ‘oic’ and acid.
Complete the following table :
Number of carbon
atoms
Molecular FormulaCnH2n+1COOH
Structural Formula Name
1HCOOH
methanoic acid
2CH3COOH
ethanoic acid
3 CH3COOH Propanoic acid
4 CH3COOH
5 CH3COOH
6 CH3COOH
.
For branched chain carboxylic acid molecules :
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
61
C
O
OH
C
O
OHH
C
O
OH
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
the name and position of the branched group is written as prefix
the smallest number is given to the carbon atom that is joined to the functional carboxyl group.
Example :
H H H O | | | // H – C – C – C – C | | | \ H H CH3 OH
2-methylbutanoic acid
Name: ……………………… Name: ………………………
5 Preparation of ethanoic acid :
Laboratory preparation through ………………of ethanol by ………………KMnO4 / K2Cr2O7 solution
H H H O | | | // H - C - C - OH + 2[O] → H - C - C + H2O | | | \ H H H OH ethanol ethanoic acid
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
62
Name: ………………………
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
Draw the set-up of apparatus for the preparation of ethanoic acid by reflux method.(preparation of ethanoic acid in laboratory)
6 Chemical properties of carboxylic acid
(i) Reacts as an acid with…………, …………………………and …………..that are more electropositive than hydrogen.
(a) Carboxylic acid + metal → carboxylate salt + hydrogen gas
(b) Carboxylic acid + base → carboxylate salt + water
(c) Carboxylic acid + metal carbonate → carboxylate salt + water + carbon
dioxide
Complete the following equations :
(a) HCOOH + Mg →
(b) C2H5COOH + KOH → + H2O
(c) CH3COOH + Na2CO3 → CH3COONa + H2O + CO2
(d) C2H3COOH + K2CO3 → + + CO2
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
63
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
(e) C2H5COOH + NaOH →
(f) C5H11COOH + K →
(ii) Carboxylic acid react with alcohol to produce ……………and………………..
with the presence of concentrated ……………..acid as a catalyst
(…………………reaction).
Carboxylic acid + Alcohol → Ester + Water
(a) C2H5COOH + → C2H3COOC2H5 + H2O
propanoic acid ethanol ethyl propanoate
(b) + C3H7OH → C2H3COOC2H5 + H2O
butanoic acid propanol propyl butanoate
(c) HCOOH + → + H2O
methanoic acid ethanol ethyl methanoate
11.7 ESTERS
1 Esters are non-hydrocarbon organic compounds containing……………,
…………………and oxygen.
2 General formula of ester : …………………………………………….
3 Functional group : ………………………………………….
O ||
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
64
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
R – C - O : Derived from carboxylic acid, name ending with ‘oate’. R is alkyl group with general formula CnH2n+1, n = 0, 1, 2, 3, ………
-R’ : Derived from alcohol, name ending with ‘yl’.
R’ is alkyl group with general formula CnH2n+1 ; n = 1, 2, 3, ………
4 Formation of esters :
Esters are produced when …………………….reacts with ……………in the presence of concentrated sulphuric acid as a catalyst (Esterification reaction) :
O O || || R - C – O-H + H-O-R’ R - C - O - R’ + H-O-H
carboxylic acid alcohol ester water
Example:
CH3COOH + C3H7OH → CH3 COOC3H7 + H2O
ethanoic acid propanol prophyl ethanoate
5 Naming of esters :
Name for esters are :first : read from the alcohol componentfollowed by : the carboxylic acid component.
Example:
CH3COOH + C2H5OH → CH3 COOC3H7 + H2O
ethanoic acid ethanol ethyl ethanoate
or
ethanoic acid ethanol ethyl ethanoate
Complete the following equations :
(i) H2SO4
HCOOH + C2H5OH → + H2O
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
65
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
(ii) H2SO4
C3H7OH + C4H9COOH → C4H9COOC3H7 + H2O
Propanol pentanoic acid water
(iii) H2SO4
C3H7COOH + C2H5OH → + H2O
(iv) H H H O H H H H H | | | || | | | | | H – C – C - C - C - OH + HO - C - C - C - C - C - H → | | | | | | | | H H H H H H H H Butanoic acid pentanol
6 Physical properties of esters :
Ester is a neutral compound with a …………….smell .
Esters have…………………; less dense than water.
Simple esters are ………………… at room temperature.
Simple esters are very volatile.
………………..in water.
7 Uses of esters :
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
66
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
Most simple esters are found naturally in fruits and……………... The fragrance of flowers and fruits is due to the presence of esters.
Example:
Ester Name Naturel source
CH3COOC5H11 Pentyl ethanoate Pineapple
C2H5COOCH3 Methyl propanoate Apple
C3H7COOC5H11 Pentyl butanoate Banana
Used in the preparation of ………………….and perfumes.
As artificial ……………………in processed of food and drinks
Used in the production of ……………………..( synthetic fibers for making textiles)
11.8 FATS
1
Fats
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
67
Fats :
A natural ester found in ………..and ……………tissue
…………….at room temperature
Oils :
A natural ester found in ………………….
……………………at room temperature
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
2
3
+ → Fats + water
R1, R2 and R3 represent hydrocarbon chains (alkyl groups) that are the same or different.
4 Saturated and unsaturated fat :
Saturated fats molecules are esters of saturated fatty acids. Saturated fatty acids
contain …………..carbon- carbon (-C-C- ) covalent bonds.
Example :
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
68
fatty acid (organic acid with long carbon chain).
Glycerol
The importance of oils and fats :
1 Fats and oil provide ………………………… bodies
2 Build …………cell and certain ………………
3 Dissolve ………………………………………..
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
Unsaturated fats molecules are esters of unsaturated fatty acids .that contain
………………..and ……………..covalent bonds between ………………their hydrocarbon chain.
Example :
5 Converting unsaturated fats to saturated fats
The double covalent bonds between carbon atoms in ………………fats are easily oxidized. When this happen, the fat has turn…………………...
Unsaturated fats can be converted to saturated fats by ………………………process
for example in the manufacture of………………... Catalyst used is ………..at ……oC :
H H H H | | Ni | | C = C + H2 C - C 180 oC | | H H
Unsaturated fat (liquid) Saturated fat (solid)
6 The effect of fats on health
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
69
Double bondSingle bond
Causes : .
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
Animals fats (saturated fats) contain higher …….cholesterol whereas vegetable oils (unsaturated fats) contain higher HDL cholesterol.
7 Advantages of palm oil in food production.
(a) …………………………………………………………………………………..
(b) …………………………………………………………………………………..
(c) ……………………………………………………………………………………
2.12 NATURAL RUBBER
1 Natural polymers are polymers that exist in nature and are not man made.
Example :
Natural polymer Monomer
Protein
2 The Structure of Rubber
Rubber is formed from the monomer……………………. Molecular formula of ……………………….is C5H8
Isopropane molecules are joined together by addition …………………process to
form the polymer of natural rubber, ………………………..:
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
70
Cholesterol
…….cholesterol
………cholesterolCauses :
…………..deposit on the artery walls
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
Isopropane (2-methylbut-1,3-diene) Poly isopropane
3 Coagulation of latex
Latex is milk like liquid obtained from tapped rubber tree. Latex is a ……………which contains suspension of rubber particles in water.
The rubber particles are made up of ………………………rubber polymers [(C5H8)n]
surrounded by a………………….. The protein membrane is ………………..charged.
The forces of repulsion between negatively charged particles prevent them from combining or coagulate.
4 Latex coagulates when : …………………………………………………………………………..
Left aside for 1 - 2 days due to bacterial action on latex. Bacteria
produces …………….that contains ……………………..( H + ) which causes coagulation of latex. Coagulate latex is semi solid
The repulsion between the negatively charged particles prevents
…………………………………………………………………………………………………Latex could not coagulation
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
71
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
When an acid is added, the …………………ion ………………..the negative charges on the protein membrane.
The rubber particles can now come …………………together………………………with
one another ………………………..of the protein membranes
The rubber molecules ……………………….with one another and entangle Causing the latex to ………………………
5 Presence of an alkali can prevent the coagulation process of latex :
Hydroxide ions, OH- from …………neutralised the hydrogen ions, H+
produced by ………………..as a result of bacterial attack on protein.
The protein membrane remain ……………..charge because there are no
more ………………………ions.
The rubber particles ………………….each other
The rubber polymers cannot ………………………….and ……………………….
.
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
72
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
6 Properties and Uses of Natural Rubber
Complete the following table :
Property Description Uses
ElasticWhen it is stretched, it straighten out.It return back to its ……………….shape once the stretching force is released.
.
Resistance to oxidation
The natural rubber polymers are easily ……………..due to presence of double bonds.
Effect of heat
When it is heated, it is soften and become……………..When it is cooled, it becomes ………and………………….
Effect of solvent
Natural rubber is soluble in organic, ……………and …………….solution.
The properties of natural rubber can be improved through the ………………process.
7 Vulcanisation of rubber :
Natural rubber is………………...(return to its original shape after stretching force released).
When the rubber is over stretched, the rubber molecules do not return to its original position. The rubber has lost…………………….
Natural rubber becomes more ……………………and elastic after vulcanisation.
In vulcanised rubber :
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
73
Rubber stripe is soaked in …………………………
solution in methylbenzene for a few hours and then dried.
Natural rubber Vulcanised rubber
4541/CHEMISTRY MODUL P3T ( TAHAP 2)
The sulphur atoms form ………………………..between the long rubber molecule.
This reduces the ability of the polymers to ……………….over each other.
The rubber molecules ……………………to its original positions after being stretched.
Properties Natural rubber Vulcanised rubber
Elasticity Less elastic
Hardness Harder
Tensile strength
END OF CHAPTER 11
JPNT 2009 CHAPTER 2 : CARBON COMPOUNDS
74