NABTEB GCE 2021 CHEMISTRY THEORY AND OBJ ANSWERS

==> *Thursday 11th February*

Chemistry (9:00am-11:30am)

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CHEMISTRY OBJ

01-10: CBABCBDADC

11-20: CBBBBCBDDC

21-30: AADBACCDDB

31-40: AAACACBBDA

41-50: BCCABCBDBC

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1a)

(i)Atom can neither be created nor destroyed,furthermore, Atoms cannot be divided into smaller particles

(ii)All matter is made up of tiny ,indivisible particles called atoms

(iii)Atoms of different elements may contains with each other in a fixed ,simple ratio to form compound atoms.

(iv)Atoms of the same elements are similar in shape and mass but differ from atoms of the other elements.

v)Atom is the smallest unit of mattee that can take part in chemical Reaction and still Retains it’s chemical properties after reaction.

1b)

i)Filtration

ii)Liquid

iii)distillation

1c)

i)

-Helium

-Neon

ii)

-Mercury

iii)

-Hydrogen H2

-oxygen O2

1c)

Empirical formular of a compound is the simplest whole number ratio of atoms of each element in the compound.its determined using Data from experiments.

1e)

i) loading…

ii) loading…

iii)

-make sulphur dioxide

-converts the sulphur dioxide into sulphur trioxode(the irresible reaction of the heart of the process)

-Convert Sulphur trioxide into Cone sulphuric acid

1ei)

Empirical Formular

Carbon Contain 0.48g

Hydrogen Contain 0.1g

Atomic Number of carbon =12

Atomic number of hydrogen =1

Therefore, C= 0.48/12= 0.04

H= 0.1/1 =0.1

Therefore,C=I and H=3

Empirical Formular =CH3

1eii)

Molecular Formular=(CH3)n=15

(CH3)n=15

[12+(3×1)]n=15

[12+3]n=15

15n=15

n=15/15

n=1

Therefore,Moleculer Formular =(CH3)

=CH3

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3ai)

Hydrocarbon is any organic chemical compound composed exclusively of hydrocarbon and carbon atoms.

3aii)

(i)The members have the same functional group

(ii)members have the same general formulars

(iii)members have almost the same chemical properties due to the same functional group.

3bi)

Name:Ethyediol or acetylenediol

Structure HO–C =C—OH

3bii)

Hydroxyl Group

3biii)

C2H2O2+H20+NaoH===>Na2C2H302+OH

3biv)

H

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H===C ==C===Na

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H

Sodium Ethanoate

3ci)

Hydrogenation Reaction

3cii)

Hydrogenation

3ciii)

Esterification

3di)

C6H12O6=====>2c2H5OH+2Co2

3dii)

Saporification

3diii)

-Diesel Fuel

-Gasoline

Diesel Oil

i)use as fuel for heavy vehicles

ii)use to power some electrical and construction machines

Gasoline

i)use as fuel for aeroplane

ii)use as fuel for transportation vehicles

Asphat

i)Use in constructing of roads

ii)use in constructions of dams and reserviances.