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