Waec Gce 2015 Chemistry Obj And Theory Answers – Nov/Dec Expo

The 100% Correct 2015 Waec Gce Chemistry Answer Answers

    CHEMISTRY OBj
    1AABABACACA
    11DABAAACDDB
    21ADDCCDCDCC
    31AACCADCDAB
    41ADDCCBAACD
    ================

    >YOU> ARE TO ANSWER 4 QUESTIONS ONLY

    ================
    (5ai)
    hydrolysis is the chemical breakdown of a compound due to
    reaction with water.

    —————————-
    3ai)
    CH3CH=CHCH# is alkene
    CH3COOCH3 is alkanoate
    CH3CH(OH)CH2CH3 is alkanol
    CH3(CH2)2CH3 is alkane
    ii) -But-2-ene
    -ethyl ethanoate
    -Butane
    -But-2-ol
    iii)CH3(CH2)2
    2bi)
    -Ultraviolet light
    ii)
    C2H6 Cl2->C2H5Cl HCl
    iii)
    -C2H5Cl Cl2->C2H4Cl2 HCl
    -C2H4Cl2 Cl2->C2H3Cl3 HCl
    -C2H3Cl3 Cl2->C2H2Cl4 HCl -C2H2Cl4 Cl4 Cl2->C2HCl5 HCl
    -C2HCl5 Cl2->C2Cl6 HCl
    iv)
    Hexachloroethane

    2ai)
    -Number of neutrons:-20,Electron
    configuration:-1s^22s^22p^63s^23p^64s^1
    -Number of neutrons:-10,Group:-7
    -Number of neutrons:10,Electron
    configuration:-1s^22s^22p^5,Group:-0
    ii)
    -X is alkali metals
    -Y is Halogens
    -Z is inert or noble gas
    iii)
    -High melting point
    -Conduct electricity in molten form

    4ai)
    Allotropy is the existence of a compound in
    two or more physical states
    ii)
    -Diamond is crystalline bond
    -Graphite is covalent bond
    iii)
    -Diamond is hard because it consist of fused
    carbon whereas graphite consists of weak
    intermolecular forces
    -This is because graphite consists of mobile
    electrons in the crystal lattice

    4bi)
    -Excess of oxygen
    -Limited supply of air
    ii)
    C(s) O2(g)->CO2(g)
    2C(s) O2(g)->2CO(g)
    iii)
    -Carbon(iv)Oxide
    -Carbon(ii)oxide

    4ci)
    -Pb(NO3)2 2NaCl->2NaNO3 PbCl2
    ii) -Molar mass of PbCl2=207 (35.5*2)
    =207 71=278g/mol
    2g will produce 1g of PbCl2
    1g will produce 1/2*5.56
    278g will produce 1/2*5.56
    =0.019
    —————————-

    1a)
    Hydrocarbon;Thisn is a compound consisting
    of carbon and hydrogen only

    1b)
    -High temperature
    -Presence of catalyst

    1c)
    Oxidation is defined as the loss of electrons

    1d)
    -The object is placed at the cathode
    -The electrolyte to be used should contain the
    electroplating metal

    1e)
    i)Pent-2-ene
    ii)Butanoic acid

    1f)
    Dalton’s law of partial pressure states that the
    total pressure of a mixture of a gases equals to sum of individual
    pressure

    1g)
    i)-They have improved mechanical properties
    -They are better in service
    ii)-Carbon
    -Iron

    1h)
    i)Electrovalent bond
    ii)Mettalic bond
    iii)Electrovalent bond

    1i)
    i)Isomers are compounds having the same molecular formular
    but different structural
    formular
    ii)Because it is inert and have a completely filled
    orbitals

    1j)
    Galvanic cells are cells that convert electrical energy to chemical
    energy

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