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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

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Question 781

jamb 1999

Which of the following gases will diffuse fastest when passed through a porous plug?
[H = 1, C = 12, N = 14, O = 16]

APropane

BOxygen

CMethane

DAmmonia

View Explanation & Discuss

Question 782

jamb 1999

56.00cm³ of a gas at S.T.P. weighed 0.11g. What is the vapour density of the gas?
[Molar volume of a gas at S.T.P = 22.4dm³]

A11.00

B22.00

C33.00

D44.00

View Explanation & Discuss

Question 783

jamb 1999

200cm\(^3\) each of 0.1M solutions of lead (II) trioxonitrate(V) and hydrochloric acid were mixed. Assuming that lead (II) chloride is completely insoluble, calculate the mass of lead (II) chloride that will be precipitated.
[Pb = 207, Cl= 35.5, N = 14, O = 16]

A2.78g

B5.56g

C8.34g

D11.12g

View Explanation & Discuss

Question 784

jamb 1998

In the experiment above, X could be a solution of

Asodium trioxonitrate (V) and ammonium chloride

Bsodium trioxonitrate (lll) and ammonium chloride

Clead (ll) trioxonitrate (V) and copper turnings

Dpotassium trioxonitrate (V) and copper turnings

View Explanation & Discuss

Question 785

jamb 1998

In the diagram above , the activation energy for the backward reaction is

A+5kJ

B+15KJ

C+25KJ

D+30KJ

View Explanation & Discuss

Question 786

jamb 1998

The diagram above represents an atom that can combine with chlorine to form

Aa covalent bond

Ban electrovalent bond

Ca hydrogen bond

Da co-ordinate bond

View Explanation & Discuss

Question 787

jamb 1998

Which of the following is true concerning the properties of benzene and hexane?

ABoth undergo substitution reaction

BBoth undergo addition reaction

CBoth are solids

DBoth can decolourized bromine water

View Explanation & Discuss

Question 788

jamb 1998

Terylene is synthesized from ethane- 1, 2-diol and benzene - 1, 4-dicarboxylic acid by?

Aaddition reaction

Bcondensation reaction

Celimination reaction

Dsubstitution reaction

View Explanation & Discuss

Question 789

jamb 1998

An example of aromatic compound is?

AC₆H₁₃OH

BC₆H₁₃CI

CC₆H₅OH

DC₆H₁₄

View Explanation & Discuss

Question 790

jamb 1998

How many structural isomers can be drawn for the non-cyclic alkanol with molecular formula C ₄H₁₀O?

View Explanation & Discuss

Question 791

jamb 1998

On cracking medicinal paraffin, a gas is evolved which gives a pop sound with a lighted splinter and an oily liquid which decolourizes bromine solution is also obtained. The products of the cracking are ?

Acarbon (IV) oxide and alkyne

Bcarbon (ll) oxide and alkene

Chydrogen gas and alkene

Dhydrogen gas and alkane

View Explanation & Discuss

Question 792

jamb 1998

One mole of hydrocarbon contains 6g of hydrogen. If the molecular weight is 54, the hydrocarbon is an?

Aalkanone

Balkane

Calkene

Dalkyne

View Explanation & Discuss

Question 793

jamb 1998

Alloys are often used in preference to pure metals because?

Ametals are too hard

Bmerals are ductile

Cmetallic properties are improve in alloys

Dalloys are a mixture of metals

View Explanation & Discuss

Question 794

jamb 1998

A common characteristic shared by iron and aluminium is that both?

Aare extracted by reduction methods

Bform only basic oxides

Cshow oxidation states of +2 and +3

Dform soluble hydroxides

View Explanation & Discuss

Question 795

jamb 1998

The metal that will react with water only in the form of steam to librate hydrogen gas is?

Acalcium

Baluminium

Ciron

Dzinc

View Explanation & Discuss

Question 796

jamb 1998

Which of the following is observed when a solution of iron (III) chloride is mixed with a solution of sodium hydroxide?

AA gas is evolved

BA deep blue precipitate is formed

CThe resultant solution turns green turns

DA brown precipitate is formed

View Explanation & Discuss

Question 797

jamb 1998

The oxide that remains unchanged when heated in hydrogen is?

ACuO

BFe₂O₃

CPbO₂

DZnO

View Explanation & Discuss

Question 798

jamb 1998

A solution containing chloride ions gives white precipitate with silver trioxonitrate(V) Solution. The precipitate will be insoluble in dilute?

AHNO ₃ but soluble in ammonia solution

BHNO₃ and ammonia solution

CHCl but soluble in ammonia solution

DHCl and in ammonia solution

View Explanation & Discuss

Question 799

jamb 1998

3CuO_(s) + 2NH_3(g) → 3Cu_(s) + 3H₂O_(I) N_2(g) (i).

2NH_3(g) + 3Cl_2(g) → 6HCl_(g) + N_2(g) (ii).

4NH_3(g) + 3O_2(g) → 6H₂O_(I) + 2N_2(g) (iii).

The reactions represented by the equations above demonstrate the?

Abasic properties of ammonia

Bacidic properties of ammonia

Creducing properties of ammonia

Doxidizing properties of ammonia

View Explanation & Discuss

Question 800

jamb 1998

A gas that turns a filter paper previously soaked in lead ethanoate solution black is?

Ahyrogen chloride

Bhydrogen sulphide

Csulphur (IV) oxide

Dsulphur (VI) oxide

View Explanation & Discuss

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