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Chemistry Past Questions

Study and practice Chemistry past questions with answers and detailed explanations. Then test your knowledge using our interactive CBT practice platform and prepare confidently for your upcoming examinations.

97 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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97 questions

Question 1 of 20 97 total questions

Question 21

waec 1997

If the atomic number of an element X is 11 and that of nitrogen is 7, the most likely formula of the nitride of X is

AX₃N

BXN₃

CX₃N₂

DN₂X

ENX₂

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Question 22

waec 1997

A sodium atom and a sodium ion have the same

Anumber of neutrons

Bnumber of electrons

Celectric charge

Delectronic structure

Echemical properties

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Question 23

waec 1997

In linear molecules, the bond angle is

A90^o

B140^o

C109^o

D120^o

E180^o

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Question 24

waec 1997

What is the most probable group of an element which is a soft, silvery white solid and reacts violently with water?

AGroup 0

BGroup 1

CGroup 4

DGroup 6

EGroup 7

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Question 25

waec 1997

Radon is used as a tracer in medical research because it

Ais monatomic

Bis radioactive

Cis a noble gas

Dhas a complete valence shell

Ehas a low boiling point

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Question 26

waec 1997

How many unpaired electrons are there in an atom of an element with the following electronic configuration? 1s²2s²2p₆

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Question 27

waec 1997

The mass number of an element is the sum of its

Aelectrons, neutrons and protons

Belectrons and protons

Cprotons and neutrons

Dorbital electrons

Evalence electrons

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Question 28

waec 1997

The phenomenon observed when dust particles collide randomly in a beam of sunlight is known as?

ATyndal effect

Bdiffusion

Cosmosis

Dbrownian movement

Edialysis

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Question 29

jamb 1997

The compound above is the product of the oxidation of

A2-methlbutan-2-ol

B2-methylbutan -1- ol

C2, 3-dimethylprop 1-ol

DPentan -2- ol

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Question 30

jamb 1997

The compound above contains

ASp ³ hybridized carbon atoms only

BSp ² hybridized carbon atoms only

CSp ³ and Sp hybirdized carbon atoms

DSp ³ and Sp ²

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Question 31

jamb 1997

Choose the correct answer from the options above. When Fehling is solution is added to two isomeric carbonyl compounds X and Y with the molecular formula C ₅H ₁₀O, compound X gives a red precipitate while Y does not react. It can be inferred that X is

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Question 32

jamb 1997

How many more isomers of the compound above can be obtained ?

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Question 33

jamb 1997

The IUPAC nomenclature of the organic compound with the above structural formula is

A3-ethyl-2,5-dimethylhexane

B4-ethyl-2,5-dimethylhexane

C3-ethyl-2,5,5 - trimethylpentane

D3-ethyl, 1,1,4-trimethylpentane

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Question 34

jamb 1997

In the diagram above the gas Y could be

Ahydrogen chloride

Boxygen

Ccarbon (IV) oxide

Dchlorine

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Question 35

jamb 1997

Use the graph above to answer this question. A sample, X, solid at room temperature, was melted, heated to a temperature of 358 K and allowed to cool as shown in OPQR.The section OP suggests that X is in the

Aliquid sate

Bsolid/liquid state

Csolid state

Dgaseous state

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Question 36

jamb 1997

Use the graph above to answer this question. A sample, X, solid at room temperature, was melted, heated to a temperature of 358 K and allowed to cool as shown in OPQR. The section PQ indicates that X is

Aa mixture of salts

Ba hydrated salt

Can ionic salt

Da pure compound

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Question 37

jamb 1997

\(\frac{1}{2}\)N\(_2\)(g) + \(\frac{1}{2}\)O\(_2\)(g) → NO(g) ∆H° = 89 KJ mol\(^{-1}\). If the entropy change for the reaction above at 25°C is 11.8 J mol\(^{-1}\), calculate the change in free energy. ∆G°, for the reaction at 25°C?

A88.71 KJ

B85.48 KJ

C-204.00 KJ

D-3427.40 KJ

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Question 38

jamb 1997

25 cm\(^3\) of 0.02 M KOH neutralized 0.03 g of a monobasic organic acid having the general formula C\(_n\)H\(_{2n + 1}\)COOH. The molecular formula of the acid is?

(C = 12, H = 1, O = 16)

AHCOOH

BC₂H₅COOH

CCH₃COOH

DC₃H₇COOH

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Question 39

jamb 1997

The synthetic detergents are preferred to soap for laundry using hard water because?

Adetergents are water soluble while soap is not

Bthe calcium salts of detergents are water soluble

Cthe magnesium salt of soap is soluble in hard water

Dsoap does not have a hydrocarbon terminal chain

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Question 40

jamb 1997

Synthetic rubber obtained by the polymerization of chlorobutadiene in the presence of sodium is called?

Ateflon

Bisoprene

Cpolythene

Dneoprene

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