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Chemistry Past Questions

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2,505 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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2,505 questions

Question 1 of 20 2,505 total questions

Question 801

jamb 1998

The addition of water to calcium oxide leads to?

Aa physical change

Ba chemical change

Cthe formation of a mixture

Dan endothermic change

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Question 802

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 803

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 804

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 805

jamb 1997

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

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Question 806

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 807

jamb 1997

In the diagram above the gas Y could be

Ahydrogen chloride

Boxygen

Ccarbon (IV) oxide

Dchlorine

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Question 808

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 809

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 810

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 811

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 812

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 813

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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Question 814

jamb 1997

The final product of the reaction of ethyne with hydrogen iodide is?

ACH₃—CHI₂

BCH₂l—CH₂I

CCH₃—CI₃

DCH₂ = CHI

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Question 815

jamb 1997

The reaction of an alkanol with an alkanoic acid in the presence of concentrated H₂SO₄ will produce an?

Aalkanal

Balkanoate

Calkanone

Dalkyne

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Question 816

jamb 1997

An undesirable paraffin in the petroleum industry which is particularly prone to knocking is?

Aiso-octane

Bn-heptane

Ciso-heptane

Dn-octane

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Question 817

jamb 1997

A sample of a substance containing only C and H burns in excess O₂ to yield 4.4g of CO₂
and 2.7 g of H₂O. The empirical formula of a substance is?

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

ACH₃

BCH₂

CCH₄

DC₂H₂₄

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Question 818

jamb 1997

Sodium hydroxide is prepared commercially from sodium chloride solution by?

Aelectrolysis using mercury as cathode

Bhydrolysis in steam using a catalyst

Celectrolysis using iron as anode

Dtreating sodium chloride with ammonia and carbon (IV) oxide

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Question 819

jamb 1997

Which of the additives could improve the quality of steel?

ASilicon

BSulphur and phosphorus

CCarbon

DChromium and nickel

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Question 820

jamb 1997

The removal of rust from iron by treatment with tetraoxosulphate (IV) acid is based on the?

Ahydrolysis of the iron

Breaction of acid with base

Coxidationof the rust

Ddehydration of the iron

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