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EXTRACTION OF SODIUM is so important to us because it is needed in several purposes.
Sodium is extracted by electrolysis of molten sodium chloride in Down’s cell
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The process involves mixing sodium chloride with calcium chloride. Calcium chloride is added to the system in order to reduce the melting point of the mixture below 600c. The iron gauze cylinder between the anode and cathode prevents the sodium and chlorine from mixing. The mixture is then electrolysed in a cell where sodium is liberated at the cathode while chlorine produced sits the anode
AT THE ANODE
AT THE CATHODE
2cl =====> Cl2(g) + 2e
Na + e ====> Na(s)
EXTRACTION OF ALUMINIUM
Aluminium is extracted from its are called bauxite
Bauxite is an impure form of hydrated aluminium oxide Al2O3. 2H2O
Extraction of aluminium involves two stages
a) Bauxite is purified to remove impurities by heating. Heating remove water as well. The
purified bauxite is dissolved in crylite Na3AlF6 so as to reduce melting point.
i) The molten mixture is then electrolysed.
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Aluminium oxide is an ionic compound which ionises as follows:
Al2O3 =====> 3O2
During electrolysis the negatively charged oxide ions, O2 are attracted to the anode where they lose electrons to form oxygen gas
AT THE ANODE
2O2 =====> O2 + 4e
The positive aluminium ions, Al3 are attracted to the cathode where they gain electron to form molten aluminium in metal.
AT THE CATHODE
Al3 + 3e ======> Al
The molten aluminium is eventually collected at the bottom of the cell.
EXTRACTION OF IRON
Iron is extracted mainly from its ares. The are is reduced in a blast furnace. The blast furnace is a steel tower lined with fireproof bricks.
A mixture of iron is coke and limestone is fed at the top of the furnace. The blast of hot air at 800c is sent into the bottom of the furnace through holes called layers
At the bottom of the furnace the coke is burnt in excess air at 1600c to form carbondioxide
C + O2 =====> CO2(g)
Carbon dioxide reacts coke higher up in the furnace to form carbon monoxide
CO2 + C =====> 2CO
Carbon monoxide is a reducing agent. It moves up the furnaces and reacts with iron are Fe2O3 at 700c to form iron and carbon dioxide
2Fe2O3 + 3CO =====> 2Fe + 3CO2
The molten iron produced flows in a thin stream to the bottom of the furnace
Limestone beings to decompose forming carbon dioxide and calcium oxide.
CaCO3 =======> CaO + CO2
Calcium oxide reacts with the earthy impurities called silicon dioxide to form a liquid slag, which is mainly calcium silicate:
CaO + si O2 ======> CasiO3
Slag
The slag also flows to the bottom of the furnace but it is less denser than molten iron, thus it floats on top of molten iron. The molten iron and the slag may run off at intervals.
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EXTRATION OF COPPER
Copper is very in the activity series and it can be extracted without chemical reduction. Copper is extracted form copper pyrites, CufeS2. The are is crushed and mixed with water and oil. Air is the blown through the mixture. In doing so the mixture becomes concentrated. Then the are is roasted to remove some sulphur.
2CufeS2 + 4O2 =======> Cu2S + 3SO2 + 3SO2 + 2FeO
Silicon is then added to the mixture and heated in the absence of air. Iron (II) oxide reacts with silicon to give iron silicate, which can be easily separated leaving behind Cu2S.
The remaining copper(s) sulphide is then reduced by heating in regulated supply of air
Cu2S + O2 =======> 2Cu + SO2
Copper is then purified by electrolysis. Pure copper is made the cathode and the impure copper the anode in an electrolytic cell containing copper (II) sulphate solution as an electrolyte.
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Electrodes reactions
At the anode: impure copper dissolves Cu =====> Cu2+ + 2e
At the cathode: copper is deposited Cu 2+ + 2e ====> Cu
PROPERTIES OF METALS
Properties of metals can be classified into physical and chemical properties
PHYSICAL PROPERTIES
Metals
i). Are solids at room temperature except mercury which is liquid
ii). Re unallowable that is they can be beaten or rolled into sheets
iii). Are ductile that is can be made into wires
iv). Are sonorous that is they makes noise when hit
v). Are lustrous that is they shine when polished
vi). Are good conductor of heat and electricity
vii). Have high tensile strength
viii). Have high densities because their atoms are very closely packed
ix). Have high melting and boiling points
CHEMICAL PROPERTIES
Metals
i) Are reducing agents that are they are electron donors metals high in the activity series donate electrons than those below it.
Na ===> Na + e
K ====> K + e
Ca2+ ===> Ca2+ + 2e
ii) With air many metals react directly with oxygen to form metallic oxides e.g.
4K + O2 ======> 2K2O
2Ca + O2 ======> CaO
iii). With water: Reactive metals such as potassium sodium and calcium react with cold water to form hydroxide and hydrogen:
2K + 2H2O ======> 2KOH + H2
Ca +2H2O ======> Ca(OH)2 + H2
However moderately reactive metals such as zinc and iron react with steam to give metallic hydroxide and hydrogen:
Zn(s) + 2H2O(g) =======> Zn(OH) (aq) + H2(g)
iv). With mineral acids: metals can replace hydrogen ion H+ in an acid and so produce salt and hydrogen gas
Mg + 2Hcl =====> Mgcl2 + H2
COMPOUNDS OF METALS
METAL OXIDES:
These are compounds of oxygen with metals
PREPARATION:
They can be prepared direct and indirect methods
i). Direct method heating metals directly in air in which a metal combine directly with oxygen
2). Mg + O2v ======> 2MgO
ii). Indirect method by thermal decomposition of salts such as metallic carbonates hydroxide or nitrate.
CaCO3 =======> CaO + CO2
Mg(OH)2 ======> MgO + h2O
2Cu(NO3)2 ======> 2CuO + 4NO2 + O2
CLASSIFICATION OF METALIC OXIDES
Metal oxide can be classified into main groups
1. Basic oxide is a metallic oxide, which react with an acid to produce salt and water only for example calcium oxide:
CaO + 2Hcl =====> Cacl2 + H2O
If soluble in water basic oxide forms an alkali
CaO + H2O ====> Ca(OH)2
2). Acidic oxide is a non metallic oxide which when dissolved in water it forms acid e.g. sulphur dioxide carbon dioxide and sulphur trioxide:
SO3 + H2O ====> H2SO4
Acidic oxides react with alkali to form a salt and water only:
SO2 + 2NaOH ====> Na2SO4 + H2O
3). Neutral oxide is an oxide of non-metal, which have neither basic nor acidic properties. Neutral oxides include nitrogen monoxide dinitrogen oxide water and carbon monoxide.
4). Amphoteric oxides are oxides, which have both basic and acidic properties. Examples of amphotertic oxides are zinc oxide, ZNO aluminium oxide, Al2O3 and lead oxide, PbO . Amphoteric oxide can react with both acid and alkali to produce salt and complex salt respectively
ZnO + 2Hcl ======> Zncl2 + H2O
ZnO + 2NaOH + H2O =====> Na2Zn (OH)4
Sodium zincates
5) . Peroxides are oxides, which contain twice as much oxygen as expected from the usual valency of element in the oxides e.g. hydrogen peroxide, H2O2 and sodium peroxide Na2O2
6). Mixed oxides are those, which react like a mixture of two simpler oxides such as trilead tetra oxide P3O4 which behaves as lead dioxide, PbO2 and lead oxide PbO.
USES OF OXIDES
i). In ointment and in some paints
ii) In cosmetic and for polishing jewellery
iii) For making glass and glazing pottery
iv) In the manufacture of planters
v) In the formation of slag
vi) As a drying agent
METAL HYDROXIDES
These are soluble oxides of metals. They are prepared either directly or indirectly
i). Direct method is by dissolving metal oxides in water
Na2O + H2O ====> 2NaOH
CaO + H2O ====> Ca(OH)2
ii). Indirect method is by reacting sodium or potassium hydroxide with aqueous solution of soluble salts such as copper (II) sulphate
CuSO4 + 2NaOH ======> Cu(OH)2 + Na2SO4
CLASSIFICATION OF HYDROXIDES
They are classified as:
i) Soluble hydroxides: These include hydroxides of group I metals: sodium hydroxide and
potassium hydroxide
ii) Insoluble hydroxides: Calcium hydroxide and magnesium hydroxide are sparingly
soluble and others are insoluble
iii) Amphoteric hydroxides: These are hydroxides of metals zinc, Aluminium and lead.
CHEMICAL PROPERTIES OF HYDROXIDES
i) Action of heat: The hydroxide of move reactive metals such as sodium hydroxide and potassium hydroxide are unaffected by heat, but those of the less reactive metals decompose to oxide and water
Cu(OH)2 =====> CuO + H2O
ii). Reaction with acids: Metal hydroxides react with acidic to form salt and water only.
KOH + HCL =====> KCL + H2O
USES OF HYDROXIDES
Some uses of hydroxides include
i). In agriculture’
ii). In mortar and plaster
iii). Bleaching
iv). In softening water
v). In quantitative analysis’
vi). In the manufacture of soap and artificial silk
vii) In the refining of petroleum and purification of bauxite
CARBONATES AND HYDROGEN CARBONATES
Carbonate occur in nature as limestone, marble, chalk calculate etc. some example of carbonates that occur naturally include zinc carbonate, iron (II) carbonate and copper (II) carbonate (malachite) sea animal shells are made of calcium carbonate
Soluble carbonates are prepared by passing carbon dioxide to an alkali
Ca(oH)2 + CO2 ======> Ca CO3
Insoluble carbonates are prepared by prepared by precipitation reaction for instance when zinc sulphate is mixed with sodium carbonate a precipitate of zinc carbonate is formed
ZnSO4 + Na2CO3 =====> ZnCO3 + Na2SO4
CLASSIFICATION OF CARBONATES
They are classified as
i) Soluble carbonates which include potassium carbonate sodium carbonate and ammonium carbonate
ii) Insoluble carbonates such as zinc carbonate, calcium carbonate lead carbonate and copper (II) carbonate
CHEMICAL PROPERTIES OF CARBONATE AND HYDROGEN CARBONATE
i) Action of heat carbonates of sodium and potassium do not decompose when heated, other metallic carbonates decompose on heating to form metal oxide and carbon dioxide
Ca CO3 =====> CaO + CO2
ii) Reaction with acids: All carbonates and hydrogen carbonates react with acids to form salt water and carbon dioxide
CaCO3 + HCL ======> CaCL2 + H2O + CO2
NaHCO3 + HCL =====> NaCL + H2O + CO2
USES OF CARBONATE AND HYDROGEN CARBONATE
Some uses of metal carbonate and hydrogen carbonate include
i) In water softening
ii) In the manufacture of glass
iii) In qualitative analysis
iv) In removal of grease
NITRATES
They are very important chemicals in industrial purposes
Nitrate is prepared by dissolving a metal carbonate oxide or on alkali in dilute nitric acid.
a) With sodium hydroxide
NaOH + HNO3 =====> NaNO3 + H2O
b) With calcium carbonate
CaCO3 + 2HNO3 ====> Ca(NO3)2 + CO2 + H2O
c) With metal oxide
PbO + 2HNO3 =====> Pb(NO3(2 + H2O
d) Reaction magnesium
Mg + 2HNO3 =====> Mg(NO3)2 + H2O
CHEMICAL PROPERTIES OF NITRATE
i) Solubility – All nitrates are soluble in water
ii) Action of heat: Decomposition of nitrates are related to the position of metals in the reactivity series.
K
Na
Nitrates of these metals decompose to nitrite and oxygen dioxide and oxygen
NaNO3 ========> NaNO2 + O2
KNO3 ========> KNO2 + O2
Ca
Mg
Al
Zn
Fe
Pb
Nitrates of there metals decompose to produce metals nitrogen dioxide and oxygen
2AgNO3 ======> Ag + 2NO2 + O2
Cu
Hg
Ag
Nitrates of there metals decompose to produce metal nitrogen dioxide and oxygen
2AgNO3 ========> Ag + 2NO2 + O2
Cu
Hg
Ag
Nitrates of there metals decompose to produce metal nitrogen dioxide and oxygen
2AgNO3 =====> Ag + 2NO2 + O2
BROWN RING TEST FOR NITRATE
A mixture of equal volumes of nitrate solution and iron (II) sulphate solution is poured in a test tube. Holding the test tube in a slanting position a slow continuous stream of concentrated sulphated sulphuric acid is power into the side of the test tube. A brown ring forms at or near the junction of the two layers and then disappear.
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USES OF NITRATES
Nitrates are commonly used in
i) The manufacture of nitric acid
ii) Manufacture of fertilizers
iii) Gun powder
CHLORIDES
Metallic chlorides can be prepared directly or indirectly
i) Direct method is by passing chlorine gas over heated metal: All metals are attacked by chlorine to for chlorides.
2Al + 3CL2 ======> 2AlCl3
2Na + cl2 =======> 2Nacl
ii) Indirect method is by reacting metal oxides, hydroxide or carbonate with dilute hydrochloric acid:
NaCO3 + 2Hcl =====> NaCL + H2O
CaCO3 + 2HCL ====> CaCL2 + H2O + CO2
Mg(OH)2 + 2HCL ===> MgCL2 + 2H2O
GENERAL CHEMICAL PROPERTIES OF CHLORIDES
i). Action with concentrated sulphuric acid. Chlorides react with conc. Sulphuric acid evolving hydrogen chloride.
NaCL(s) + H2SO2 (aq) ====> NaHSO4 (s) + HCL(g)
ii). Volatility. Being move volatile than most salts chlorides are usually used in flame test for detecting certain metals.
TEST FOR CHLORIDE
i). The following test can be used to identify chloride in a liquid mixture. A little nitric acid is added to a suspected chloride solution and then silver nitrate solution a white precipice of silver chloride id formed.
ii). The following test can be used to identify chloride in a solid mixture: Concentrated sulphuric acid is added to the suspected chloride a gas that produced thick fumes with ammonia is formed.
USES OF CHLORIDE
Some common uses of chloride include
i). Manufacture of dry batteries soap common salt etc.
ii). In soldering
iii). In petroleum industry
SULPHATES
Soluble sulphates can be prepared by dissolving a metal an oxide a carbonate hydroxide or of metal in dilute sulphuric acid:
Mg + H2SO4 ====> MgSO4 + H2
CuO + H2SO4 ====> CuSO4 + H2O
CaCO3 + H2SO4 ====> CaSO4 + CO2 + H2O
Zn(OH)2 + H2SO4 ====> ZnSO4 + 2H2O
Insoluble sulphate can be prepared by adding dilute sulphuric to lead or barium ions. For example when dil. H2SO4. to barium chloride a white precipitate of barium sulphate is formed:
Bacl2 + H2SO4 =====> BaSO4 + 2Hcl
CHEMICAL TEST FOR SULPHATES
Identification of sulphate ion an aqueous solution can be conducted as follows If a barium chloride is added to a suspected soluble sulphate followed by dilute hydrochloric acid a white precipitate of barium sulphate, which is insoluble in excess, is formed
Ba++(aq) + SO4(aq) =====> BaSO4(s)
USES OF SULPHATES
Sulphites are commonly used
i) In the manufacture of commonly salt paper sulphur fertilizers dioxide inketc.
ii) In the plaster casts
iii) As white pigment
NON – METALS AND THEIR COMPOUNDS
A non-metal is an element, which has more electrons in its outermost shell than its period. Non- behaviour they are oxidising agent
DIFFERENCES BETWEEN METALS AN NON- METALS
METALS
NON - METALS
i) Have high melting and boiling points
i) Have low melting and boiling points except carbon
ii) Mostly solid except mercury which is a metal
ii) Gas or volatile liquid except carbon which is solid
iii) Good conductors of heat and electricity
iii) Generally bad conductor except carbon
iv) Have high tensile strength
iv) Have low tensile strength
v) Have high density except sodium and potassium
v) Have low density except carbon
vi) Are malleable
vi) Are not malleable
vii) Are sonorous
vii) Are not sonorous
viii) Are ductile
viii) Are not ductile
ix) Are lustrous
ix) Are not lustrous
x) Form positive ions by losing electrons Na =====> Na+ +e
x) Form negative ions by gaining electrons: CL- + e ====> Cl
xi) Form basic oxides when dissolved in water they give alkalis:
K2O + H2O ====> 2KOH
xi) Usually form acidic oxides other oxides are neutral. If dissolved in water acidic oxides form acids:
SO3 +H2O ====> H2SO4
xii) Replace hydrogen in acid to form salt
xii) Do not form salt in this way.
OXIDISING PROPERTY OF NON – METALS
Non – metals react by gaining electrons to become negatively charged ions:
A monovalent non-metal gains one electrons
Cl +e ====> CL-
A divalent non- metal accepts two electrons
O + 2e =====> O2
An element that accepts electrons is called an oxidizing agent (oxidant)
ELECTRONEGATIVITY
It is the ability of an element to accept electrons
Elements with higher electronegavity are strong oxidants while low electro negativity are weak oxidizing agent (oxidant). Strong oxidants can displace weak oxidants from their compounds e.g.
2KI + cl2 ======> 2Kcl + I2
In the above reaction chlorine has higher electro negativity than iodine so chlorine so chlorine is a stronger oxidant.
CHLORINE
Chlorine is not found free in nature The principle source of chlorine is sodium chloride Nacl found in sea water chlorine is prepared in the laboratory by oxidation of cone HCL acid by manganese (iv) oxide the mixture of manganese (iv) oxide and concHCL are heated in the flask.
IMAGES
MnO2 + HCL ====> MnCL2 + 2H2O + CL2
Chlorine is also prepared in the laboratory by the oxidation of potassium manganese (vii) by concHCL
2KmnO54(aq) + 16HCL(aq) ===> 2KCL + 2MnCl2 + 8H2O + 5CL
PHISICAL PROPERTIES OF CHLORINE
i) A greenish yellow gas with choking irritating smell
ii) Denser than air
iii) Bleachers damp litmus
CHEMICAL PROPERTIES OF CHLORINE
i) With water it dissolves in water to give a greenish acidic solution called hypochlorous acid (chloric (II) acid)
Cl2 + H2O ====> HOCL + HCL
Chloric (I) acid bleaches vegetable dyes by oxidation converting the dye to colourless compounds.
Coloured substance + HOCL ====> colourless +HCL
ii) With hydrogen. Chlorine continues to burn in hydrogen to form hydrogen chloride
H2 + cl2 =====> 2HCL2
iii) With metals: when passed over heated iron chlorine reacts with it forming iron (II) chloride:
iv) With alkali:
a) Chlorine reacts with cold dilsdodium hydroxide solution to give a mixture of chloride and hypo chlorite
NaOH + CL2 =====> NaCl + NaOCL + H2O
a) Chloride reacts with hot concsodiumhydroxide solution to give sodium chlorate
6NaOH + 3CL2 =====> 5NaCL + NaCLO3 + H2O
v) Chlorine as an oxidizing agent .It causes oxidation of hydrogen sulphide to sulphur:
H2S + CL2 ====> 2HCL + S
USES OF CHLORINE
The most common uses of chlorine include
i) As a bleaching agent
ii) As a germicide for killing germs in drinking water
iii) As a disinfectant
iv) In the manufacture of hydrochloric acid, chloroform and DDT.
HYDROGEN CHLORIDE:
It is prepared in the laboratory by the action of conc. H2 So4 on sodium hydroxide:
PHYSICAL PROPERTIES OF HYDROGEN CHLORIDE
i). It is a colourless poisonous gas white with a pungent smell.
ii). It is soluble in water.
iii). It is an acidic gas changing blue litunus led It is denser than air.
CHEMICAL KPROPERTIES OF HYDROGEN CHLORIDE
i). With metals. Hydrogen chloride reacts with metals to give slat and hydrogen:
Mgs + 2Hcl g) =====>mg Cl 2 (s) + H2 (9)
With bases: Hydrogen chloride reacts metal oxide or hydroxide forming salt and water only. This is neutralization reaction:
Na OH + HCL =====>Na Cl + H2O
CaO + 2HCl =====>Ca Cl2 + H20
With metal carbonate: It reacts with metal carbonate liberating salt, carbordioxide and water:
Ca CO3 + 2H Cl ====>CaCl2 +CO2 +H20
CHEMICAL TEST FOR HYDROGEN CHLORIDE
If a gas jar containing hydrogen chloride is brought mouth to mouth with one containing ammonia white dense clouds of ammonium chloride are formed.
USES OR HYDROGEN CHLORIDE
It is commonly used in
i) The manufacture of hydrochloric acid
ii) Qualitative and quantities analysis
SULPHUR
Sulphur is a non-metal element found in-group vi just below oxygen. It occurs both in free state and in combined states as sulphides of z Inc and lead. Sulphur is a constituent of all living matter as it is found in certain proteins of hair and eggs.
EXTRACTION:
Sulphur is extracted from some underground deposits by the Frasch process. A scientist Herman Frasch kin inverted this process 19 the century. A large pipe of about 25 cm in diameter is sunken to the sulphur deposits (beds). Two pipes of smaller diameters are lowered inside the large pipe. A hole is made to the sulphur bed superheated water under pressure is forced down the outside tube to melt the sulphur. Hot compressed aired is sent done the narrow miner piper. This forces foam of sulphur, water and air back to the surface through the middle pipe.
The molten sulphur is collected din large tanks where it solidifies and water drains away.
FRASCH PROCESS
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ALLOTROPES OF SULPHUR.
Sulphur exists in two allotropes: rhombic and monoclic sulphur
RHOMBIC SULPHUR
MONOCLINIC SULPHUR
i) Yellow translucent crystals
ii) Stable at temperature below 96c0
iii) Octahedral crystals
iv) Melting point is 114 c0
v) Transparent amber crystal
vi) Instable below 96 c0
vii) Needle – shaped crystals
viii) Melting point is 119 c0
PLASTIC SULPHUR
When solid sulphur is heated it melts and form mobile liquid. At this point molecules of sulphur are moving facedly around each other. If sulphur is heated further the liquid thicker and continued heating to 444 C0 makes the liquid molecules move mobile and dif this liquid is poured into a beaker of cold water a substance called plastic sulphur is formed. This is an elastic rubber=- like substance.
OXIDISING PROPERTY OF SULPHUR
Sulphur combines directly with melts to from metal sulphides:
Fe + S ====> Fe S
St2e =====>S2-
In this reaction sulphur accepts electron, whence kits oxidizing property
USES OF SULPHUR
Sulphur is used in the following ways.
i) For the manufacture of sulphuric acid. Fertilizers, gunpowder germicides dougs, dyes, medicated fitment etc.
ii) For spraying fruit tolls such as cash nut tree = to control fungal infections.
iii) For making hard and strong by the process called vulcanisation.
SULPHURIC ACID H2 SO4
It is manufactured by the contact process, which has the following stages:
i) Obtaining sulphur dioxide by heat rig sulphur in air:
S (S) + O2 (G) ====> SO2 (G)
ii) Obtaining Sulphur dioxide over caladium catalyst to about 450 C0.
SO2 + O2 ======>SO3 4 DH = - 107KJ mol-1
The forward reaction is exothermic and so lowering temperature favours the forward reaction. Optimum temperature for this reaction is between 400 Co and 500c0
iii) Dissolving sulphur trioxide in concentrated sulphuric acid to give a substance called oleum.
SO3 + H2 So4 =====>H2 S2 O7
iv) The adding oleum to the correct amount of water to produce sulphuric acid. 4
H2 S2 O7 + H2 O ===> 2H2 So4
CONTACT PROCESS
PROPERTIES OF SULPHURIC ACID
As an acid:
a) With metals such as z in C iron and other moderately reactive metals it gives hydrogen:
b) Zn+ Hz SO4 ====> Cu So4 + H2O
c) With metal hydroxide, it forms slat and water
2NaOH + H2SO4 ====> Na2SO4 H2O
d) With carbonate, it releases carbon dioxide when added to metal carbonate:e)
Mg Co3 + H2 SO4 =====> Mg SO4 + CO22+_ H2O
ii) As a dying agent and dehydrating agent. It has a strong affinity for water that is why it is used to dry many gases such as hydrogen, oxygen, nitrogen, chlorine etc@
i) With hydrates, it removes water of crystallization:
Cu So4 %H2O H2 So4 CUSO4 + 5h2o
Blue white
ii) With carbohydrates, it reacts with moist sugar to produce a black mass of carbon:
C12 H22 O11 ==>h2 So 4 12C + HH2O
iii) As an oxidizing agent, hot conc. H2 SO4 is reduced by
a) Moderately reactive metals such as zinc copper and aluminium:
CU + 2H2SO4 ====>CuSo44 + 2h20 + s
b) Non- metals such as carbon, sulphur etc.
C + 2h2 So4 ====>2H2O + Co2 + 25O2
1V) As a catalyst. It catalyses the reaction between carboxylic acid and an alcohol:
CH3 COOH + C2H5 OH CONC. H2 SO4 ===>H34COOC2 H5 + H2O
USES OF SULPHURIC ACID
It is mainly used
1) As a raw material for the manufacture of many substances such as fertilizers, paints, pigment and dyes, artificial fibres, detergents and chemicals.
2) In accumulator and car batteries
3) In refining of petroleum
4) In extraction of metals
5) As a catalyst.
SULPHUR DIOXIDE, SO2
Sulphur dioxide is a colourless gas with a poisonous pungent smell. It is very soluble in water.
CHEMICAL PROPERTIES.
i) With water: Sulphur dioxide dissolves kin water to produce an acidic solution of sulphurous acid.
SO2 + H2O ====> H2 SO3
ii) As an acid. If sulphur dioxide is bubbled into sodium hydrogen sulphate is produced.
NaOH + SO2 ===>Na H SO3.
iii) As a reducing: sulphur dioxide in the presence of water is a powerful reducing agent e.g. with Iron (111) chlorine.
2Fe Cl3 + 2H2O + SO2 ====>2fe Cl2 + 2Hcl + H2 SO4
iv) As an oxidizing agent: a) sulphur dioxide reacts with hydrogen sulphide to form sulphur and water.
So2 + 2H2S =====>3s + 2H2O
Sulphur dioxide, in the above reaction, is reduced to sulphur.
b) Sulphur dioxide supports the burning of magnesium:
Mg +So2 2mg O + S
As an oxidizing agent, sulphur dioxide is reduced to sulphur.
USES OF SULPHUR DIOXIDE
The following are the common uses of sulphur dioxide:
i) In the manufacture sulphuric acid, fumigants etc.
ii) For food perpetration
iii) Acting as a bleaching agent.
iv) As a liquid solvent for refining petroleum
NITROGEN:
Nitrogen is the most plentiful gas of the air as it makes 78% of the earth atmosphere. It is the first member of Group V of the periodic table. Nitrogen exhibits a valency of five.
LABORATORY PREPARATION:
Removing carbnondioxide and oxygen in air by kmeans of conc. NaoH and copper prepare it respectively: Concentrated sodium hydrochloride solution kin the conical absorbs carbon dioxide from air.
NaOH + CO2 ====>NaH Co3
Then the gas is passed over led hot copper turnings where oxygen is unmoved by reacting with copper turnings to form copper (ii) oxide:
Cu + O2 ====> CuO.
Eventually nitrogen gas is collected over water.
PROPERTIES OF NITROGEN.
Nitrogen is very uncreative gas; however it combines directly, when heated
i) W ith metals such as magnesium and calcium to give nitrogen gas is collected over water.
Mg + N2 ===>Mg3N2
Ca + N2 ===>Ca3 N2
ii) With hydrogen in Haber process to from ammonia
N2 + 3H2 ===>2NH3
USES OF NITROGEN
It is mainly used in
i) Haber process for production of ammonia
ii) Manufacture of nitric acid, dyes, fertilizers and explosive.
iii) Food packaging.
iv) Refrigeration.
AMMONIA, NH3
It is a nitrogen hydride – Ammonia is very important in industry and agriculture.
LABORATORY PREPARATION:
It is prepared by heating a mixture of solid ammonium chloride and calcium hydroxide.
Ca (OH) 2 + NH4Cl =====>2NH3(g) + CaCl2 (5) + 2H2 O(g)
Water vapour is removed from the ammonia gas by passing the gas though a column of calcium oxide.
PHYSICAL PROPERTIES.
Ammonia is
i) A colourless gas with a sharp chocking smell
ii) Less denser than air
iii) Very soluble in water
iv) The only alkaline gas as it turns a moist red titunus blue.
CHEMICAL PROPERTIES.
Ammonia gas
1) Burns in pure oxygen with a pale green brown flame to form nitrogen and water:
4NH 3 + 302 ====>2N2 + 56HzO
ii) Is a reducing agent as kit reduces metal oxides to their respective metals e.g.
CUO + 2NH3 ====>Cu + 3H2O + N2
iii) React with hydrogen chloride forming a white cloud of ammonium chloride:
NH3 + Hcl ====>NH4 Cl.
iv) Reacts with water to from ammonium hydroxide.
NH3 + H2O ===> NH4 OH.
USES OF AMMONIA.
Some uses of ammonia include:
i.). In laundry work by removing temporary hardness of water.
ii.). In the manufacture of fertilizers, nitric acid, nylon and plastics, ammonium chloride etc.
iii.). In refrigerating plants.
iv.). In converting nitric acid to fertilizers.
THE FOUNTAIN EXPERIMENT FOR SOLUBILITY
A drop of water is allowed to fall from the jet into the flask Ammonia in the flask dissolves in the drop of water: This reduces pressure inside the flask. The drop of pressure rushes water up the tube into the flask creating a fountain.
CARBON:
It is non- metallic element found in-group I view of the periodic table of element. Carbon shows the valence os 4 in many compounds. It is the most interacting of all elements as all living things are made of carbon and their compounds and its is also the word’s reliable source of energy. Carbon occurs as free element in diamond and graphite, and is present in nature in carbon dioxide, carbonate and shells of animals.
ALLOTROPES OF CARBON
Carbon exhibits allotropy. Allotropy is the existence of an element in more than one form without change of states. The different forms of an element in the same state are called allotropes. Allotropes of carbon are graphite, Hammond and amorphous carbon. Each allotrope has a different structure and so different physical properties:
GRAPHITE:
The atoms are arranged in definite layers. Within each layer carbon atoms are bonded to three others by strong covalent bonds. Between these layers there are weak forces of attraction. These weak forces enable the layers to slide over each other easily. The fourth electron is not attached to any other particular atom so it is free electron makes graphite to be good conductor of electricity and heat. The weak forces between are its layers make graphite soft and greasy in texture.
Hexagonal structure of graphite
Uses of Graphite
Some uses of graphite include:
i) In making lead pencil
ii) Used ads a lubricant due to its soft and greasy property
iii) Used as electrodes man electrolytic cell
iv) Used for making crucibles.
v) Used as a moderator in nuclear pile.
DIAMOND:
In diamond each of the carbon atom is covalently joined to four other carbon atoms arranged tetrahedral. This type of bonding gives rise to that dimensional structure in which forces that hold the carbon atoms are equally strong in all directions. This structure causes the extreme hardness of diamond and hence its high very high melting point. All the covalent electrons are diamonds are used to form covalent bonds, so there are no mobile electrons available to enable diamond to conduct electricity. This is why diamond is a poor conductor of heat and electricity.
Tetrahedral structure of diamond.
Uses of Diamond
i). Due to its extreme hardness, diamond is used for drilling devices and glasscutters.
ii). It is use a gemstone.
ARMORPHOUS CARBON.
It is a strong reducing agent:
i). With hot concentrated sulphuric acid, carbon is oxidized to carbon dioxide:
2H2 SO4 + C ====>Co2 + 2H20 + 2So2
ii) With hot concentrated nitric acid, carbon is oxidized to carbon dioxide.
4HNO3 + C =====>Co2 + 2H20 + 4NO2
iii) Carbon reduces the oxides of lead and copper to their respective metals:
CuO + C ====>Cu + Co2
PbO + C ====>b + CO2
CARBONDIOXEDE, CO2
It is one of the mixing gases in air. Carbon dioxide is also found in various natural gases. It is one of the products of all decaying organic matters. Carbon dioxide is very important in life as green plants in the process of photosynthesis use it.
LABATO
LABARATORY PREPARATION:
Carbon dioxide can be prepared by the action on dilute hydrochloric on marble chips, Ca CO3 collected by down ward delivery. Conc. Sulphuric acid in a conical flash is for drying the gas.
PHYSICAL PROPERTIES:
I) It is a colourless gas with faint smell.
II) It does not burn but it extinguishes a burning sling.
III) It is denser than air
IV) It turns damp blue litmus red.
V) It is fairly soluble in water.
CHEMICAL PROPERTIES:
i) With limewater, ca (OH) 2. Carbon dioxide turns limewater due to the formation f calcium carbonate.
Ca (OH) 2 + CO2 ====> CaCO3 + H20
Excess carbondioxede forms a clear solution of calcium hydrogen carbonate:
CaC03 + H2O + CO2 =====> Ca (HCO3) 2
ii) With water: it dissolves slightly in water giving weak carbonic acid.
H2O + CO ====>H2CO3
iii) With a sodium hydroxide. Carbon oxide is absorbed by it giving sodium carbonate and water.
2NaOH + CO2 ====> Na2 CO3 + H2O
As an oxidizing agent: Magnesium continue to turn in carbon dioxide gas giving magnesium carbon dioxide gas giving magnesium oxide and carbon.
2Mg + CO2 ===>2mg O+C.
In this reaction Magnesium has been oxidized to magnesium oxide.
IMPORTANT USES OF CARBONDIOXIDE.
i) In fire extinguishers
ii) In making mineral water and beer
iii) In aerated drinks
iv) In the manufacture of sodium hydrogen carbonate and sodium carbonate by
solved process.
v) By plants in photosynthesis.
vi) In the manufacture of urea.
vii) In baking bread or cake.
viii) In refrigeration as dry ice for keeping ice cold.
ORGANIC CHEMISTRY.
It is the study of the compounds of carbon excluding the oxidise, carbide, carbonate and hydrogen carbonate. Organic chemistry entirely deals with the substances found in, and produced by living things (plants and animals. Carbon forms millions of different compounds because carbon atoms can join together in long, straight, branched or chains or rings. Also carbon atoms can form single or multiple bonds between atoms.
All organic compounds contain carbon together with one or more other elements such as oxygen, hydrogen, chlorine, nitrogen and sulphur. Guide oils, petroleum, dyes, lipids, carbohydrates, proteins, alcohol, drugs, textile are rubber are all organic compounds. All living things are made of organic compounds. All living things are made of organic compounds. Inorganic compounds, on the other hand, are obtained form mineral sources.
DIFFERENCES BETWEEN KORGANIC AND INORGANIC COMPOUNDS.
ORGANIC COMPOUNDS
INORTANIC COMPOUNDS
1) Are either plant and or animal origin?
1) Are of mineral origin
2) Covalence is more common
2) Both covalence and elector valence are common
3) May sometimes contain atoms linked kin rings or chains
3) Contains neither chains nor rings.
4) Exhibits isomerism
4) No isomerism
FRACTIONAL DISTAILLATION OF CRUE OILS
Fractional distillation is a process of separating a mixture of liquids by making use of their differences of boiling points. It involves vaporising and condensing to from the liquid. Crude oils contain many hydrocarbons. These hydrocarbons are separated by fractional distillation as different hydrocarbons boil at different boiling points. In fractional distillation crude oil is heated to about 400co and vapour is passed into fractionating column, which contain trays and bubble caps. The components are further broken into smaller components. The move volatile comprehends go up the tower while those with higher boiling points condense at the lower trays.
HYDROGARBONS.
Hydrocarbons are compounds, which contain only carbon and hydrogen. They are classified into two main groups namely saturated and unsaturated hydrocarbons. Saturated hydrocarbons are hydrocarbons which contain air least one multiple between its carbon atoms e.g. – C == C - and - === C – .Alkenes and alkynes are unsaturated hydrocarbons.
HOMOLOGOUS SERIES.
It is a series of compounds sharing similar structures. Members of the same homologous series are called homologues.
CHARACTERISTICS OF HOMOLOGOUS SERIES.
All members of the some homologous series.
i) Are represented by the same formula
ii) Are made by similar method
iii) Have similar chemical properties
iv) Show gradual changes in physical properties.
v) Each member differs from the next by the addition of – CH2 group.
FAMILIES OF HYDROCARBONS.
There are three families for hydrocarbons:
i) Alkenes.
ii) Alkenes
iii) Alkynes.
ALKANES.
These are saturated hydrocarbons represented by a general formula Cn H2n+ 2 where n + 1, 2, 3, 4, etc.
Alkenes are also known as paraffin.
The first members of alkenes.
NAME
MOLECULAR
FORMULA
STRUCTURAL FORMULA
CONDENSED FORMULA
PHYSICAL STATE.
Methane
CH4
H
IH-C-H
I
H
H
CH4
Gas
Ethane
C2H6
H H
I I
H-C-C-H
I I
H H
CH3 CH2 CH3
Gas
3. Propane
C3H8
H-H-H
H-C-C-C-H
I I I
H H H
CH3CH2CH3
Gas
4. Butane
C4H10
I – I –I – I
H-C-C-C-C-H
I I I I
H H H H
CH3CH2CH2CH2CH3
Liquid
5. Pentane
C5 h12
H H H H H
H –C –C –C –C–C-H
I I I I I
H H H H H
CH3CH2CH2CH2CH2CH3
Liquid
6. Hexane
C6h14
I I I I I I
H-C – C- C- C- C –C –H
I I I I I I
H H H H H H
CH3 CH2 CH2 CH2 CH2 CH3 CH3
Liquid.
ALKAYL RADICAL.
An alkyl l radical is a monovalent group of atoms obtained by removing hydrogen atom from the alkenes molecule. The genital molecular formula of alkyl radical’s is CnH2n+1
Some examples of alkyl radicals:
NAME OF ALKANE
MOLECULAR FORMULA
NAME OF ALYL RADICAL
MOLECULAR FORMULA
1. Methane
CH4
Methyl
-CH3
2. Ethane
C2 H6
Ethyl
-C2H5
3, Propane
C3H8
Propyl
C3H7
4. Butane
C4 H10
Butyl
-C4H9
ISOMERISM KAND I UPAC.
Is omerism is the existence of compounds having the same molecular formula but different structural formula; and compounds, which have the same, molecular are called isomers.
RULES OF NOMENCLATURE.
1. The longest chain of atoms is considered the parent chain e.g. c- c- c-c-c-
2. The carbon atoms in the parent chain are numbered to locate the position where hydrogen atom has been replaced by an alkyl radical or functional group.
The numbering sequence should start at the end, which will give the lowest number.
1) The complete flame of the compound consists of
i). The name of the parent chain.
ii) The name of the attached alkyl group.
iii) The numbered position of the group.
ISOMERS OF ALKANES.
1.Butane has two Isomers.
a) H H H H
H - C- C - C- C – H
I I I I
H H H H
n. Butane, CH4
B) H H H
H- C- H- H- H
I I I
H I H
H- C – H
I
H
2- Methyl propane, C4 tt10
2.Pentane has three isomers.
H H H H H
I I I I I
a) H- C- C- C- C- C- -H I I I I I H H H H H
I I I I
N – pentane, C5H12.
b) H- C- C- C- C- H
I I I I
H H H H
I
2 – METHYL PROPANE, C5 H12
C) H
I
H H- C- H H H
I I I I H- C- C- C- C- H -H
I I I I
H H O H H
I
H
2,2,-DIMETHYL PROPARE, c5 h12
Note that the isomer cannot be formed buy depicting the structure as
H H H H
H C- C- C -C
-H H- C- 4
I
H
CYCLOALKANES.
Alkenes can form innings named by using the prefix cycloid- followed by the corresponding alkenes e.g.
A) HC2 CH2
CH2 Cyclopropane
CH2
b) H2C CH2
H2C CH2
Cyclobutons
a) H2C CH2
H2C CH2
CH2
Cyclohexane
d) H2C CH2
H2C CH2 Cyclopentane
ALKENES.
These are unsaturated hydrocarbons containing at least one double bond between its tow carbon atoms. >C = C <.
Alkenes are represented by a general formula, Cn H2n- where n = 2, 3, 4 etc. They are sometimes known as olefins. Alkenes are named by substituting – ene for –are form the corresponding alkenes. The first five members of alkenes are:
NAME OF ALKENE
MOLECULAR FORMULA
STRUCTURAL
FORMULA
CONDENSED
FORMULA
STATE
1. Ethene
C2H4
H H
C C
H H
CH2 CH2
Gas
2. Propene
C3 H6
H H I I I
H H H
CH2CH CH2
Gas
3. Butrene
C4 H8
H H
I I
H –C -C =C -C -H
I I I I
H H H H
CH3 CH2 CH2 CH3
Gas
4. Pentene
C5 H10
H H H H H
I I I I I
H - C - C- C- C-C -
I I I H H H
CH3 CH CH CH2 CH2 CH3
Liquid
5. Hexene
C6 H12
H H H H
I I I I
H- C-C = C- C -C- C -4
I I I I I I
H H H H H H
CH3 CH CH CH2 CH2 CH3
Liquid
ISOMERS OF ALKENES.
Isomers of alkenes are determined by the position of the double bonds and the arrangement of carbon skeleton for example butane has the following Isomers:
a) H H
H Butane.
b) H H I I
H- C - C = C- C - 4
I I I I
H H H H
But –2 –ene
C) H H
H- C- C = C
H H
H-C-H I H
2- Methyl pentane.
ALKYNES.
These are unsaturated hydrocarbons containing at least one triple bond between its carbon atoms.
–C ≡≡ C-
Alkynes are represented by a general formula Cn H2n –2 where n is a whole number greater than 1.
Alkynes are named by substitution the endings –yne for – are from the corresponding alkenes.
The first five members of alkynes are:
NAME OF ALYNE
MOLECULAR FORMULA
STRUCTURAL FORMULA
CONDENSED FORMULA
PHYSICAL STATE.
1.Ethyne
C2H2
H-C ≡≡C-H
CH CH
Gas
≡≡
2. Propyne
C3H4
H
I
H – C ≡≡C - C - H
H
CH C CH3
Gas
3. Butyne
C3 H6
H H
H-C ≡≡ C- C- C- H
I I I
H H H
CH CH2 CH3
Gas
4. Pentyne
C5 H8
H H H
I I I
H- C ≡≡C- C- C-H
I I I
H H H
CH CH2 CH2 CH3
Liquid.
5. Hexyne
C6 H10
H H H H
H- C ≡≡ C-C- C- C- C- H
I I I I
H H H H
CHC CH2 CH2 CH2 CH3
Lquid
ISOMERS OF ALYNES.
Isomers of alkynes are determined kby the position f a triple bond and the arrangement kof the carbon skeleton.
For example:
i) Isomers of butyne include:
H H
I I
a) H – C ≡≡ C – C –C-H
I I
Butyne
H H
I I
b) H – C- C ≡≡ C- C -H
I I
H H
But – 2-yne
2) Isomers of pentyne are
I I I
A) H- C ≡≡ C- C- C- C – H
I I I
H H H
Pentyne
H H
B) H- C – C ≡≡ C –C –C –H
I I I
H H H
Pent – 2 –yne.
H
I
C) H – C ≡≡ C- C- C- H
I
H
H-C-H
I
H
3- METHYL But –2-yne.
CRACKING.
It is the breaking down large hydrocarbon molecules into smaller molecules of petrol and gases e.g. Conversion of decade into octane and ethane:
C10 H22 ===>C8 H18 +C2 h4
CHEMICAL PROPERTIES OF ALKANES.
1) Combustion: alkenes are flammable, they burn in
a) plentiful supply of air to form carbon dioxide and water
CH4 + 2O2 ====>co2 +2h2O
Mono chloromethane
CH3 CL + CL2 ===> CH2+ CL2 + HCL
Dichloromethane
CH2 CL + CL2 CCL4 + HCL
Tetra chloromethane
(Carbon tetrachloride)
CHEMICAL PROPERTIES OF ALKENES.
1). Combustion: Alkenes burns with a hot luminous flame to form carbon dioxide and water:
C2 h4 + 302 =====> 2co2 + 2H2O
2) Addition reaction: Alkenes are unsaturated hydrocarbons; they readily form compounds by addition with many substance.
Monochloro ethane
c) With conc. H2 SO4. Alkenes react additively with conc. Sulphuric acid to give ethyl hydrogen sulphate.
C2H4 + H2 SO4 ===>C2 H5 HSO4
Ethyl hydrogen sulphate.
POLYMERIZATION
It is a process whereby large (macro) molecule called a polymer is built by the combination of a number of smaller molecules celled monomers
e.g. H H H H H H
I I I I I I
CH2 = CH2 + CH2 = CH2 + CH2 + CH2 = CH2 ===>-C -C- C- C- C- C
I I I I I I
H H H H H H
CHEMICAL PROPERTIES OF ALKYNES.
1. Combustion: Alkynes burns in air with a luminous flame to give carbon dioxide and water:
E c2 H2 + 5o2 ====>4 CO2 + 2H2 O
2. Addition reaction, being unsaturated alkynes reacted additively with many substances e.g.
a) With hydrogen:
C2 h2 + h2 =====> C2 H4
b) With chlorine:
C2H2 +CL2 ====>C2H2CL2
c) With hydrogen chloride.
C2h2 + HCL ====>C2H3CL
ALKANOLS (ALCOHOLS)
These are organic compounds, which contain a hydroxyl group –OH ATTACHED TO AN ALYL GROUP. They are represented by a general formula Cn H2n+ 1OH. –OH is called the functional group f the alcohol because it often determines the way in which the molecule will react; Alcohols are named by replacing “ol”.
The first five members of alcohol:
1. Methanol
(Methyl alcohol)
Ch3 OH
H
I
H – C – OH
I
H
CH3 OH
2. Ethanol
(Ethyl alcohol)
C2H5OH
H H
I I
H- C- C- OH
I I
H H
CH3 CH2 OH
3. Propane (propyl alcohol)
C3 h7 oh
H H H
I I I
H – C- C- C – OH
H H H H
CH3 CH2 CH2OH
4. Butanol (butyl alcohol)
C4H9OH
H H H H H
I I I I
H- C- C- C- C –C –OH
CH3 CH2 CH2 CH2OH
5. Pentanol (Pentyl alcohol)
C5H11 OH
H H H H H
I I I I I
H – C- C- C- C- C- OH
I I I I I
CH3 CH2 CH2 CH2 CH2 OH.
Glucose ethanol
Fermentation is the slow decomposition process of organic substances in the presence of enzymes as catalyst and usually a companied by the evolution of carbondioxide and heat. Ethanol s produced is made stronger by heating to its boiling point and the vapour condensed. This process it’s called fractional distillation. .
Isomers of alcohol are determined by the position of the functional group and the arrangement the carbon skeleton for example, isomers of butanol are
H H H H H
I I I I I
a) H - C- C- C- C- C-OH
I I I I I
H H H H H
Butanol.
H H H H
I I I I I
B) H – C- C- C- C- H
I I I I I
H H OH H
Butan –2-ol
CHEMICL PROPERTIES OF ETHANOL
1) Combustion: Ethanol burns in air with a blue flame giving carbon dioxide and water:
C2 H5 OH + 3O2 ====>2CO2 + 3H2O
2) With sodium: Ethanol react with sodium to give hydrogen and sodium ethnocide
2 C2 H5 OH + 2NA ====>2C2 H5 ONA + H2
Sodium ethoxide.
3) With concentrated sulphuric acid: Ethanol reacts with conc. H2 so4 to form ethyl by drogen sulphate and water:
C2 h5 OH + H2 SO4 ====> C2 H5 HSO4 +H20
4) With ethanoic acid: Ethanol reacts with organic acid on warning with conc. H2 so 4 to form ester and water:
CH3 COOH + C2h5OH ====> CH3 COOC2 H5 +H2O
This type of reaction is called esterification.
Esterfication is the reaction of alcohol and organic acid, warning with a few drops of conc. H2SO4 as a catalyst to form ester and water.
SOME DIFFERENCES BETWEEN ESTERIFICATION AND NEUTRALIZATION REACTION.
ESTERIFICATION
NEUTRALIZATION
1.It is slower because kit is between molenules
1. It is faster because it involves ions.
2. It is reversible
2. It irreversible
3. Esters are covalent compounds
3. Salts are ionic compounds
4. Reactant are alcohol and organic acid
4. Reactants are mineral acid and base.
5. Products are esters and water
5. Salts and water
6. Catalyst present
6. No catalyst is involved.
CARBOXYLIC ACIDS
These are organic compounds, which contain carboxylic group – COOH as a functional group attached to an alkyl radical. They are represented by a general formula Cn H2n + 1 COOH. When wine or beer is left exposed to the atmosphere for long-time it changes to vinegar due t the action of bacteria some natural sources of organic acids are vinegar, milk and citrus fruits. Organic acids are named by replacing the “e” enclung of the corresponding alkane by “oic acid”.
The following are the first five members of alcohols:
CARBOXYLIC ACID
MOLCULAR FORMULA
STRUCTURAL FORMULA
CONDENSED FORMULA
I. methanoic acid (formic acid)
H COOH
O
H
H – C- OH
HCOOH
2. Ethanoic acid (Acetic acid)
CH3 COOH
H O
I H
H – C- C- C OH
I
H
CH3 COOH
3. Propanoic acid
C2 H5 COOH
H H O
I I II
H – C- C- C- OH
I I
H H
CH3 CH2 COOH
4. Butanoic acid
C3 H7 COOH
H H H O
I I I I II
H- C- C- C- C- C- OH
I I I I I
H H H H
CH3 CH2 CH2 COOH
5. Pentanoc acid
C4 h9 COOH
H H H H O
I I I I II
H- C- C- C- C- C- OH
I I I I
H H H H
CH3 CH2 CH2 CH2 COOH
LABORATORY PREPARATION OF ETHANOIC ACID.
Ethanoic acid is prepared by the oxidation of alcohol.
When wine or beer is left exposed to the atmosphere it is oxidized in dilute solution:
CH3 CH2 OH [O] CH3 COOH
1. Acidic behaviour : being a weak acid, ethanoic acid is slightly ionised in dilute solution:
Ch3 COOH =====>CH3 COO- + H+
2. With NaOH: ethanoic acid reacts sodium hydroxide neutralizing it to for sodium ethanoate and water:
3. With Na2 CO3: Ethanoic acid reacts with sodium carbonate producing sodium ethanoate, carbon dioxide and water
4. With ethanol: Ethanoic acid reacts with ethanol kin the presence of a few drops of conc. H2 SO4 to give ester and water. This reaction is called etherification.
CH3 COOH + C2 H5 OH ====>CH3 COO C2 H5
ISOMERS OF CARBOXYLIC ACIDS.
Their isomers are determined by the branching of isomerism because it is always at the end of carbon chain.
For examples isomers of pentanoic acid are:
MA
Fat /oil + sodium hydroxide ===>sodium steerage + glycerol alcohol.
That is glycerol + Alkali ====>soap + glycerine Stearate
This type of process is known as saponification.
SOIL CHEMISTRY
Soil is the upper layer of the earth in which plants trees etc grow. It is formed from parent rock by weathering
Weathering is the process of breaking down rocks or big stones into small particles that make up the soil. Weathering is influenced by the following Factors:
1) Nature of parent rocks. It a affects the soil texture and permeability of water. There are three main types of rocks from which soil originates :Igneous rock, sedimentary rock and metamorphic rock. Igneous rocks are formed by solidification of molten lava of volcano pour. Sedimentary rocks are formed by breakdown of the soil deposited in an area over a long period of time metamorphic rocks are formed from pre-existing rocks which undergo change in composition and texture due to pressure and heat associated with earths movements.
2) Climate .It include rainfall, temperature and wind rainfall helps the weathering by dissolving soluble compounds in the rocks. The dissolved compounds in turn break the soil to the smaller particles, which can be carried by winds. Temperature influences the physical and chemical reaction of soil.
3) Living things .In the soil b burrowing animals turn the soil and mix up the top and subsoil’s and also provide enough soil aeration. These actions change the characteristics of soil.
4) Time the type and nature of soil a soil depends on the length of time by which the parent rock has been exposed to weathering process
SOIL TEXTURE
Soil texture refers to the relative proportions of different particle sizes of soil .The particles in the soil are classified according to their sizes as clay silt, fine sand course sand fine gravel and gravel.
SOIL STRUCTURE
It refers to the shape and way the soil particles are held together. There are 4 structural types of arrangement of soil particles
1). Plate like structure in which soil particles are arranged ion the horizontal plates. They are found in the upper layers of virgin soil
2). Prismatic structure in which soil particle are arranged in vertical plates. They occur in subsoil horizons
3). Block like structure in which the particles form blocks which have irregularly six faces
4). Comb structure in which the particles develop sphere like structure
SOIL REACTIONS
The soil reactions arte determined by the concentrations of H+ and OH- in the soil. The H+ ions make the soil acidic while OH ions make the soil basic. When the concentration of H+ ions is greater than OH ions is smaller than that of OH- the soil is said to be basic. However when the concentration of OH- the soil is said to be neutral.
SOIL pH
It is measure of the acidity or alkality of soil. Soil pH measured on a pH scale, which is a scale of numbers ranging from 1 to 14. Most soils range between pH 3.5 and pH11. Soils with pH below 7 are acidic. Soils above 7 are basic. Soils with pH of 7 is neutral
Image under processing
MANAGEMENT OF SOIL pH
When the soil pH is too high or too low the activities of microorganisms living in the soil are hindered. This will in turn affect the soil texture and structure. Soil acidity can be corrected by liming. Liming is the process of adding to the soil substances that contain cations in order to reduce soil acidity. Calcium and magnesium salts are commonly used as liming substances
These liming substances when added to the soil they raise the content of exchangeable cations.
PLANT NUTRIENTS
Plant nutrients play an important role for the proper growth of plants. Nutrient elements have to be supplied to plants in right amounts and propitiations. Different have different nutrient requirement
These nutrient elements required by plants are classified into two main groups:
i) Trace elements, which are required by plants in small quantities .The most important trace elements, are manganese, zinc, copper, boron and chlorine. Trace elements are sometimes known as microelements
ii) Macro- elements are those elements required by plants in relatively large amounts. Phosphorus, sulphur, calcium, magnesium, potassium, nitrogen and iron.
SPECIFIC FUNCTIONS OF MARCRO – ELEMENTS
Each element has got a specific function to plant. The function of one element is associated by the function of other elements. Thus all elements must be used together
NITROGEN: Its functions
i) Makes proteins in plant cells
ii) Forms part of the chlorophyll molecule
iii) Promotes growth of plants
Deficiency of nitrogen causes yellowing of leaves due to mad equate production of chlorophyll and plant growth is reduced
POTASSIUM: Its functions
i) Increases the efficiency for manufacturing carbohydrates
ii) Helps in the proceed of making proteins
iii) Activities enzymes
iv) Increases efficiency of photosynthesis
Deficiency of potassium causes mottled appearance of the older leaves.
PHOSPHOUS: its functions
i) Delevelops not growth
ii) Increaser grain yield for cereals
iii) Hastens crop maturation
iv) Essential for the process of nitrogen fixation in legumes
Deficiency of phosphorus causes poor root growth and reduction in uptake of all minerals
CALCIUM: Its functions
i) Activates enzymes
ii) Forms salt linkages in the middle lamella
Deficiency of calcium causes chlorosis of young leaves
MAGNESIUM: its functions
i) Forms parts of the chlorophyll
ii) Activates certain enzymes’
Deficiency of magnesium causes chlorosis, which begins between the veins of older leaves.
SULPHUR-it is important in the formation of amino acids
Deficiency of sulphur causes reduced growth of plants organs and yellowing of leaves
IRON-its functions
i) Required in photosynthesis and respiration
ii) Required for the synthesis of chlorophyll
iii) Activates enzymes
Deficiency of iron causes chlorosis especially in young leaves and inhibition of photosynthesis and respiration
SOIL FERTILITY
A fertile soil one that provides all the essential plant nutrients in sufficient and balanced amounts needed for healthy growth of plants. Thus a fertile soil for one crop is not necessarily productive for other plants.
LOSS OF SOIL FERTILITY
Soil fertility can be lost by
i) Poor farming methods such as monocropping and continues cropping, Monocropping is growing one type of crop at the same area every season
ii) Leaching .It is the removal of nutrients from the region where they are available for the plant to the lower horizons of soil profile. Plants nutrients are dissolved and carried down below the react of plant roots
iii) Change of pH in strongly acidic weakly acidic soil lead to the unavailability of same nutrients materials
iv) Flooding in flooding the plant nutrients are carried away from the soil by the moving water
v) Soil erosion it is the removal of topsoil through the action of wind and water causing the land to be depleted of nutrient materials
vi) Burning plant remains and bushes. This exercise destroys the plant nutrients.
MAINTENANCE OF SOIL FERTILITY
Soil fertility can be maintained by the following measures
i) Adopting good farming methods such as crop rotation and contour farming
ii) Prevention of soil erosion by forestation controlled grazing and avoidance of uncontrolled forested
iii) Addition of organic manures and inorganic fertilizers
iv) Mulching it is placing a layer of organic material on top of the soil
v) Prevention of leaching
vi) Use of good harvesting practices
SOIL EROSION
It is the removal of fertile topsoil from one place to another leaving behind less fertile soil
AGENTS OF SOIL EROSION: there are two main agents of erosion, which are water and wind
CAUSESS OF SOIL EROSION
i) Poor farming methods such as monocropping
ii) Burning of vegetation makes the land bare and become susceptible to soil erosion by wind
iii) Deforestation this is cutting down truses with out replacement
iv) Overgrazing this is keeping a large number of animals in small areas destroying soil texture and removes ground cover
PREVENTION OF SOIL EROSION
The following measures are commonly used to prevent soil erosion
i) Adopting good farming practise such as crop rotation contour farming terracing that is proper stocking rate
ii) Reforestation that is plating true
iii) Avoidance of uncontrolled bush fires
iv) Adopting good harvesting practises
ORGANIC MANURES
These are wastes from natural resources these wastes can be from animal and or plants. There are four main types of organic manures:
i) Farmyard manures, FYM. These are decayed wasters urine and faeces mixed with plant materials each as straw, sawdust, leaves grass etc
ii) Composite manures these are decayed organic matter of plant and or animal origin gathered and prepared by a farmer
iii) Green manures They are usually prepared by a farmers by growing a crop and then ploughed into the soil
While it is green. Green manure is very important because it improves structure and nutrient of the soil by adding organic matter to the soil
4) Kroal manures are those obtained from bomas.
FERTILIZERS
These are inorganic manures added to the soil so as to improve its plant nutrient status. Fertilizers commonly used in Tanzania in large scales include
1) SA - sulphate of ammonium (NH4) 2SO4
2) ASN- Ammonium sulpha nitrate NHJ4SO4NO3
3) CAN-calcium ammonium nitrate CaNH4NO3
4) Urea- CO (NH2) 2
5) DAP-Diammonium phosphate
6) TSP- Triple superphgosphate
7) SP-single super phosphate
8) NPK
ADVANTAGES OF NATURAL MANURES
Some advantages include
i) Increases the activities of microbes in the soil
ii) Improve the humans content of the soil
iii) Reduce the effect of water and wind erosion
iv) Improve soil structure aeration and water infiltration
v) They are cheap
DISADVANTAGES OF NATURAL MANURES
Some disadvantages include
i) They are bulky there fore they are difficult to handle or transport
ii) They may herb our insects pesta and diseases
iii) They may spread weeds
iv) They are needed in large amounts during its application
v) They have high moisture content this gives a problem in storage and transport
vi) Difficult to determine quality as they are unbalanced in relation to each other
DIFFERENT METHODS OF FERTILIZER APPLICATION
Fertilizers can be applied in solid or liquid form the following is the best methods of applying fertilizers
1) Broad casting this is scattering uniformly dry fertilizer over the surface
2) Top dressing –This is scattering dry fertilizer around the base of the plant
3) Spraying using hand or inechanical machine
4) Pellet seed .The seed is enclosed in a pellet of fertilizer
5) Placing a calculated amount of fertilizer in the planting hole when the crop is planted
POLLUTION
It is any process, which leads to a harmful increase in the amount of chemical substance in the environment. A harmful substance present environment in the wrong place in the wrong amount and at a wrong time is known as a pollutant
TYPES OF POLLUTION
Pollution is classified into
1) Air pollution a wide speed air pollutant is smoke from fossil fuels by industry in homes and in vehicles
2) The smoke contains particles of dust, which are mainly carbon. The dust particles settle on plant leaves, which in turn limit photosynthesis transpiration and gaseous exchange by blocking up the stomata. Carbon monoxide produced by the engines due to incomplete burning of organic fuels is poisonous. This gas if inhaled in large quantities react with blood red pigment to form carbonxyhaemoglobin which causes insufficient oxygen transportation
3) Sulphur dioxide reacts with water in the atmosphere to form sulphuric acid, This acid damages people’s lungus and plant leaved .It also corrodes buildings and statues
Air pollution also causes destruction of ozone layer. This layer is found at the top of the atmosphere it prevents the penetration of harmful ultraviolet light from the sum to the earth’s surface. Ultraviolet radiation causes skin burns and kills unicellular organisms
METHODS OF PREVENTING AIR POLLUTION
Air pollution can be prevented by
i) Reducing combustion of fuel by using an alternative smokeless source of energy such as electricity and solar power
ii) Using catalytic converter which acts as a device to speed up reactions which involves pollution gases converting the in into harmless products
2. Water pollution: The main sources of water pollutants sewage, oil chemical waste products and agricultural chemicals are spilled out into the sea lakes and rivers in huge amounts of daily all over the would. Spillage of oils is a big problem in oil exporting countries as much oil is spilled during loading and unbending. If not treated sewage put into rivers and or lakes may contain bacteria’s. These microorganisms on reaching the river or lakes they multiply quickly. They respire aerobically and use so much oxygen that there is not enough oxygen for other animals as a result these animals die to lack of oxygen. Chemical waste products from industries may cause death of aquatically animals if they are let discharged into sea lakes or rivers. Horbicides such as dioxin is a pollutant which is highly poisonous to man and animals.
METHOD OF PREVENTING WATER POLLUTION
The most common method of preventing water pollution is by removing pollutants by treating sewages before letting it into rivers and lakes. Avoidance of letting oils directly into sea lakes. Lakes or rivers is of sound mind too
3. Terrestrial pollution: This involves damping of dirty materials on the lend to make it not inhabitable .The main land pollutant include litter agrochemical in forms and transfers of toxic wastes. Some man made materials such as plastics nylon etc.do not decay and their damping in land fills may destroyed natural habitats provide a breeding ground for vectors and may cause evolution of poisonous gases. Agrochemicals such fertilizers herbicides sprayed directly on soil or crops may sometimes kill beneficial inserts and animals. Transfer of toxic waste from developed to underdeveloped countries where they are damped is still a major threat to hanuman’s healthy life as some of the wastes are radioactive which are lethal.
MATHODS OF PREVENTING TERRESTRIAL POLLUTION
The best ways of preventing land pollution
i) Recycling can reduce the amount of refuse bottles
ii) Packaging materials and proper should be recycled
iii) Banning of toxic materials such as DDT
iv) Constructing free flowing sanitation system.
