Waec Chemistry Obj And Theory 10th April Free Expo

Waec 2018 chemistry And Obj Answers – May/June Expo

*CHEMISTRY ANSWERS*

1a) Fermentation is 
the chemical breakdown of a substance by bacteria, yeasts, or other microorganisms, typically involving effervescence and the giving off of heat.

4b) Dalton's law of partial pressure states that in a mixture of gases, which do not react chemically together, a gas will exert a partial pressure, which is the pressure, it will exert if it is kept alone in the vessel.


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(2ci)
- Chemical and allied products industries
- sunshine oil and chemical industries
- Eleme petrochemical industries
(2cii) source of raw materials
Nearness to market
Source of amenities
(2ciii)
-Pollution of air (surrounding)
-Land excavation and improper with disposal
(2di)
Ag2O(s) +H2O2= 2Ag(s)+ O2(g)+H2O(l)
(2dii)
H2O2 + Cl2 => 2HCl(g) + 2H2)(l)
(2e)
-It is an inert gas
-It is slightly denser than air
-It is slightly soluble in water
5a)
1.Water Gas
2.Producer Gas
ii)Water Gas
iii) Both the hydrogen and Carbon(ii) Oxide in
water gas burn in air to release a lot of
heat,this makes it a better fuel
Iv)
1.Producer Gas
02(g) + N2(g) + 2C(s)-->2CO(g) +N2 + heat
2.Water Gas
C(s) +H2O(g)-->CO(g) + H2(g)
5b(i)Thermoplastics can be soften repeatedly
by heat and remoulded..
Thermosets cannot be soften or melted by heat
and remoulded once they are formed
ii)i.Bakelite
ii.Polythene
iii)
1.Plastic items can be manufactured at very
low costs by using moulds and good
manufacturing process
2.Raw materials for the manufacturing of
plastics are readily and cheaply available from
the refining of crude Oil
3.Plastics can be tailor made to our exact
requirements, because of wide applications.
3a)
From the passage of steam through a mass of
hot coke at
a very high temperature (about 1000 oC).
The water gas is mixed with more steam and
passed over iron
(III) oxide (as catalyst) at 450 o C. More
hydrogen is produced
and carbon(II) oxide gets oxidized to
carbondioxide. I.e.
The carbondioxide is removed by dissolving the
above products in water under 30 atm pressure
- CO2 dissolves.
The gas is then passed through copper(I)
methanoate in
ammonia solution under pressure to absorb
any trace of carbon(II) oxide which might be
present as impurity if not
removed - the hydrogen produced is pure.
3aii)
C (s) + H 2 O(g) → CO (g) + H 2(g)
3aiii)
I. by the action of a dilute strong acid on
metals, such as zinc:
Ii. by reaction amphoteric metals with a strong
base, such as sodium hydroxide:
Iii. by electrolysis of water:
3b)
I. Decrease in temperature shifts reaction
towards product
side.
Ii. increase in pressure shifts reaction towards
reactant side.
Iii. Increase in concentration of CO product
side.
3ci)
Condensation polymerisation is a process
whereby many
small monomer molecules join together to
form one large polymer, with water, or some
other small molecule formed at the same time.
3cii)
I. polyamides
Ii. polyacetals
3ciii) CH3−COO−CH2−CH3,
3d)
Allotropy is the existence of a chemical
element in two or more forms, which may
differ in the arrangement of
atoms in crystalline solids or in the occurrence
of molecules that contain different numbers of
atoms.
3dii)
a) diamond,
b) graphite
3diii)
Diamond is used for cutting hard substance.
Graphite is used to
make brake linings, lubricants, and molds in
foundries
LOADI

NG...(2ci)
- Chemical and allied products industries
- sunshine oil and chemical industries
- Eleme petrochemical industries
(2cii) source of raw materials
Nearness to market
Source of amenities
(2ciii)
-Pollution of air (surrounding)
-Land excavation and improper with disposal
(2di)
Ag2O(s) +H2O2= 2Ag(s)+ O2(g)+H2O(l)
(2dii)
H2O2 + Cl2 => 2HCl(g) + 2H2)(l)
(2e)
-It is an inert gas
-It is slightly denser than air
-It is slightly soluble in water
5a)
1.Water Gas
2.Producer Gas
ii)Water Gas
iii) Both the hydrogen and Carbon(ii) Oxide in
water gas burn in air to release a lot of
heat,this makes it a better fuel
Iv)
1.Producer Gas
02(g) + N2(g) + 2C(s)-->2CO(g) +N2 + heat
2.Water Gas
C(s) +H2O(g)-->CO(g) + H2(g)
5b(i)Thermoplastics can be soften repeatedly
by heat and remoulded..
Thermosets cannot be soften or melted by heat
and remoulded once they are formed
ii)i.Bakelite
ii.Polythene
iii)
1.Plastic items can be manufactured at very
low costs by using moulds and good
manufacturing process
2.Raw materials for the manufacturing of
plastics are readily and cheaply available from
the refining of crude Oil
3.Plastics can be tailor made to our exact
requirements, because of wide applications.
3a)
From the passage of steam through a mass of
hot coke at
a very high temperature (about 1000 oC).
The water gas is mixed with more steam and
passed over iron
(III) oxide (as catalyst) at 450 o C. More
hydrogen is produced
and carbon(II) oxide gets oxidized to
carbondioxide. I.e.
The carbondioxide is removed by dissolving the
above products in water under 30 atm pressure
- CO2 dissolves.
The gas is then passed through copper(I)
methanoate in
ammonia solution under pressure to absorb
any trace of carbon(II) oxide which might be
present as impurity if not
removed - the hydrogen produced is pure.
3aii)
C (s) + H 2 O(g) → CO (g) + H 2(g)
3aiii)
I. by the action of a dilute strong acid on
metals, such as zinc:
Ii. by reaction amphoteric metals with a strong
base, such as sodium hydroxide:
Iii. by electrolysis of water:
3b)
I. Decrease in temperature shifts reaction
towards product
side.
Ii. increase in pressure shifts reaction towards
reactant side.
Iii. Increase in concentration of CO product
side.
3ci)
Condensation polymerisation is a process
whereby many
small monomer molecules join together to
form one large polymer, with water, or some
other small molecule formed at the same time.
3cii)
I. polyamides
Ii. polyacetals
3ciii) CH3−COO−CH2−CH3,
3d)
Allotropy is the existence of a chemical
element in two or more forms, which may
differ in the arrangement of
atoms in crystalline solids or in the occurrence
of molecules that contain different numbers of
atoms.
3dii)
a) diamond,
b) graphite
3diii)
Diamond is used for cutting hard substance.
Graphite is used to
make brake linings, lubricants, and molds in
foundries
LOADI
NG...

4b) Dalton's law of partial pressure states that in a mixture of gases, which do not react chemically together, a gas will exert a partial pressure, which is the pressure, it will exert if it is kept alone in the vessel.

1ai)



 Fermentation is the process in which a substance breaks down into a simpler substance. Microorganisms like yeast and bacteria usually play a role in thefermentation process, creating beer, wine, bread, kimchi, yogurt and other foods. Fermentation comes from the Latin word fermentare, meaning “to leaven.

5a)
1.Water Gas
2.Producer Gas
ii)Water Gas
iii) Both the hydrogen and Carbon(ii) Oxide in water gas burn in air to release a lot of heat,this makes it a better fuel
Iv)
1.Producer Gas
02(g) + N2(g) + 2C(s)-->2CO(g) +N2 + heat
2.Water Gas
C(s) +H2O(g)-->CO(g) + H2(g)
5b(i)Thermoplastics can be soften repeatedly by heat and remoulded..
Thermosets cannot be soften or melted by heat and remoulded once they are formed
ii)i.Bakelite
ii.Polythene
iii)
1.Plastic items can be manufactured at very low costs by using moulds and good manufacturing process
2.Raw materials for the manufacturing of plastics are readily and cheaply available from the refining of crude Oil
3.Plastics can be tailor made to our exact requirements, because of wide applications.
3a)
From the passage of steam through a mass of hot coke at
a very high temperature (about 1000 oC).
The water gas is mixed with more steam and passed over iron
(III) oxide (as catalyst) at 450 o C. More hydrogen is produced
and carbon(II) oxide gets oxidized to carbondioxide. I.e.
The carbondioxide is removed by dissolving the above products in water under 30 atm pressure - CO2 dissolves.
The gas is then passed through copper(I) methanoate in
ammonia solution under pressure to absorb any trace of carbon(II) oxide which might be present as impurity if not
removed - the hydrogen produced is pure.
3aii)
C (s) + H 2 O(g) → CO (g) + H 2(g)
3aiii)
I. by the action of a dilute strong acid on metals, such as zinc:
Ii. by reaction amphoteric metals with a strong base, such as sodium hydroxide:
Iii. by electrolysis of water:
3b)
I. Decrease in temperature shifts reaction towards product
side.
Ii. increase in pressure shifts reaction towards reactant side.
Iii. Increase in concentration of CO product side.
3ci)
Condensation polymerisation is a process whereby many
small monomer molecules join together to form one large polymer, with water, or some other small molecule formed at the same time.
3cii)
I. polyamides
Ii. polyacetals
3ciii) CH3−COO−CH2−CH3,
3d)
Allotropy is the existence of a chemical element in two or more forms, which may differ in the arrangement of
atoms in crystalline solids or in the occurrence of molecules that contain different numbers of atoms.
3dii)
a) diamond,
b) graphite
3diii)
Diamond is used for cutting hard substance.
Graphite is used to

make brake linings, lubricants, and molds in foundries

Esterification is the process by which alkanol react with alkanoic acid in d presence of a catalyst such as sulphuric acid n heat to produce Ester n water only
1ai)


 Fermentation is the process in which a substance breaks down into a simpler substance. Microorganisms like yeast and bacteria usually play a role in thefermentation process, creating beer, wine, bread, kimchi, yogurt and other foods. Fermentation comes from the Latin word fermentare, meaning “to leaven.
5a)
1.Water Gas
2.Producer Gas
ii)Water Gas
iii) Both the hydrogen and Carbon(ii) Oxide in water gas burn in air to release a lot of heat,this makes it a better fuel
Iv)
1.Producer Gas
02(g) + N2(g) + 2C(s)-->2CO(g) +N2 + heat
2.Water Gas
C(s) +H2O(g)-->CO(g) + H2(g)
5b(i)Thermoplastics can be soften repeatedly by heat and remoulded..
Thermosets cannot be soften or melted by heat and remoulded once they are formed
ii)i.Bakelite
ii.Polythene
iii)
1.Plastic items can be manufactured at very low costs by using moulds and good manufacturing process
2.Raw materials for the manufacturing of plastics are readily and cheaply available from the refining of crude Oil
3.Plastics can be tailor made to our exact requirements, because of wide applications.
3a)
From the passage of steam through a mass of hot coke at
a very high temperature (about 1000 oC).
The water gas is mixed with more steam and passed over iron
(III) oxide (as catalyst) at 450 o C. More hydrogen is produced
and carbon(II) oxide gets oxidized to carbondioxide. I.e.
The carbondioxide is removed by dissolving the above products in water under 30 atm pressure - CO2 dissolves.
The gas is then passed through copper(I) methanoate in
ammonia solution under pressure to absorb any trace of carbon(II) oxide which might be present as impurity if not
removed - the hydrogen produced is pure.
3aii)
C (s) + H 2 O(g) → CO (g) + H 2(g)
3aiii)
I. by the action of a dilute strong acid on metals, such as zinc:
Ii. by reaction amphoteric metals with a strong base, such as sodium hydroxide:
Iii. by electrolysis of water:
3b)
I. Decrease in temperature shifts reaction towards product
side.
Ii. increase in pressure shifts reaction towards reactant side.
Iii. Increase in concentration of CO product side.
3ci)
Condensation polymerisation is a process whereby many
small monomer molecules join together to form one large polymer, with water, or some other small molecule formed at the same time.
3cii)
I. polyamides
Ii. polyacetals
3ciii) CH3−COO−CH2−CH3,
3d)
Allotropy is the existence of a chemical element in two or more forms, which may differ in the arrangement of
atoms in crystalline solids or in the occurrence of molecules that contain different numbers of atoms.
3dii)
a) diamond,
b) graphite
3diii)
Diamond is used for cutting hard substance.
Graphite is used to

make brake linings, lubricants, and molds in foundries