100% Real Waec Gce 2015 Chemistry Obj And Theory Answers.

By 09:55 Thu, 17 Sep 2015 Comments


CHEMISTRY OBJ:

1-10: AABABACACA

11-20: DABAAACDDB

21-30: ADDCCDCDCC

31-40: AACCADCDAB

41-50: ADDCCBAACD

(1a)

Hydrocarbon;This 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

(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

(2aii)

-X is alkali metals

-Y is Halogens

-Z is inert or noble gas

(2aiii)

-High melting point

-Conduct electricity in molten form

(2bi)

This is because of decreasing atomic number

(2bii)

Relative atomic mass is the mass of an

element in

one atom of carbon-12

(2biii)

V.D=R.A.M/2

V.D=32/2

=16

(3ai)

CH3CH=CHCH# is alkene

CH3COOCH3 is alkanoate

CH3CH(OH)CH2CH3 is alkanol

CH3(CH2)2CH3 is alkane

(3aii)

-But-2-ene

-ethyl ethanoate

-Butane

-But-2-ol

(3aiii)

CH3(CH2)2C2H5Cl+HCl

(3biii)

-C2H5Cl+Cl2->C2H4Cl2+HCl

-C2H4Cl2+Cl2->C2H3Cl3+HCl

-C2H3Cl3+Cl2->C2H2Cl4+HCl

-C2H2Cl4+Cl4+Cl2->C2HCl5+HCl

-C2HCl5+Cl2->C2Cl6+HCl

(3biv)

Hexachloroethane

(4ai)

Allotropy is the existence of a compound in

two

or more physical states

(4aii)

-Diamond is crystalline bond

-Graphite is covalent bond

(4aiii)

-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

(4bii)

C(s)+O2(g)->CO2(g)

2C(s)+O2(g)->2CO(g)

(4biii)

-Carbon(iv)Oxide

-Carbon(ii)oxide

(4ci)

-Pb(NO3)2+2NaCl->2NaNO3+PbCl2

(4cii)

-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

=0.019C2H3Cl3+HCl

-C2H3Cl3+Cl2-


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