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Chemistry Past Questions

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99 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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99 questions

Question 1 of 20 99 total questions

Question 31

jamb 2017

The gas that can be collected by downward displacement of air is

Achlorine

Bsulphur (IV) oxide

Ccarbon (IV) oxide

Dammonia

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Question 32

jamb 2017

An oxide XO₂ has a vapour density of 32. What is the atomic mass of X?

A20

B32

C14

D12

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Question 33

jamb 2017

According to Charle's law, the volume of a gas becomes zero at

A−100°c

B−273°c

C−373°c

D0°c

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Question 34

jamb 2017

The carbon atoms on ethane are

Asp² hybridized

Bsp³ hybridized

Csp⁴ hybridized

Dsp hybridized

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Question 35

jamb 2017

The densities of two gases, X and Y are 0.5gdm^-3 and 2.0gdm^-3 respectively. What is the rate of diffusion of X relative to Y?

A0.1

B0.5

C2.0

D4.0

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Question 36

jamb 2017

The reddish–brown rust on iron roofing sheets consists of

AFe³ + (H₂O)₆

BFeO.H₂O

CFe₂O₃.XH₂O

DFe₃O₄.2H2₂O

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Question 37

jamb 2017

The IUPAC nomenclature of the structure above is

A3-methybut-3-ene

B2-methylbut-1-ene

C2-ethylprop-1-ene

D2-methylbut-2-ene

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Question 38

jamb 2017

Calculate the mass of copper deposited when a current of 0.5 ampere was passed through a solution of copper(II) chloride for 45 minutes in an electrolytic cell. [Cu = 64, F = 96500Cmol^-1]

A0.300g

B0.250g

C0.2242g

D0.448g

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Question 39

jamb 2017

The diagram above. Y is

Afused CaO

BH₂O

CNaOH

DConcentrated H₂SO₄

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Question 40

jamb 2017

In the diagram above. X is

ASO₃

BSO₂

DH₂S

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Question 41

jamb 2017

Cu\(_2\)S(g) + O\(_2\)(g) → 2Cu + SO\(_2\)(g)
What is the change in the oxidation number of copper in the reaction?

A0 to + 2

B0 to + 1

C+ 1 to 0

D+ 2 to + 1

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Question 42

jamb 2017

The alkyl group is represented by the general formula

AC_nH₂n

BC_nH₂n − 2

CC_nH₂n + 1

DC_nH₂n + 2

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Question 43

jamb 2017

The enzyme used in the hydrolysis of starch to dextrin and maltose is?

Alipase

Bamylase

Cinvertase

Dzymase

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Question 44

jamb 2017

The reaction of halogens with alkanes in the presence of sunlight is an example of

Aoxidation reaction

Baddition reaction

Chydrogenation reaction

Dsubstitution reaction

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Question 45

jamb 2017

Calculate the amount in moles of silver deposited when 9650C of electricty is passed through a solution of silver salt [= 96500 Cmol^-1]

A0.05

B10.80

C10.00

D0.10

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Question 46

jamb 2017

Tin is unaffected by air at ordinary temperature due to its?

ALow melting point

BWeak electropositive character

CHigh boiling point

DWhite lustrous appearance

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Question 47

jamb 2017

The mass of silver deposited when a current of 10A is passed through a solution of silver salt for 4830s is – (Ag = 108 F = 96500(mol-1)

A54.0g

B27.0g

C13.5g

D108.0g

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Question 48

jamb 2017

The shape of ammonia molecules is

Atrigonal pyramidal

Boctahedral

Csquare planar

Dtetrahedral

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Question 49

jamb 2017

\(^{226}_{88}Ra\) → \(^x_{86}Rn\) + alpha particle

A226

B220

C227

D222

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Question 50

jamb 2017

When ΔH is negative, a reaction is said to be

Aendothermic

Bexothermic

Creversible

Dionic

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