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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.

49 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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49 questions

Question 1 of 20 49 total questions

Question 11

jamb 1990

.....................P....Q.....R......S
Proton..............13....16....17.....19
Electron............13....16....17.....19
Neutron.............14....16....35.....20

Which of the four atoms P,q,R and in S in the above data can be described by the following properties relative atomic mass is greater than 30 but less than 40; it has an odd atomic number and forms a unipositive ion in solution?

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Question 12

jamb 1990

A basic postulate of the kinetic theory of gases is that the molecules of a gas move in straight lines between collisions. This implies that?

Acollisions are perfectly elastic

Bforces of repulsion exist

Cforces of repulsion are in equilibrium

Dcollision are inelastic

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Question 13

jamb 1990

Equal volumes of CO,SO2, NO2 and H2S were released into a room at the same point and time. Which of the following gives the order of diffusion of the gases to the opposite corner of the room?
(S = 32, C = 12, O = 16, N = 14, H = 1)

ACO, SO₂,NO₂,H₂S

BSO₂,NO₂,H₂S,CO

CCO,H₂S,SO₂,NO₂

DCO,H₂S,NO₂,SO₂

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Question 14

jamb 1990

The volume occupies by 1.58g of a gas at s.t.p is 500cm³. What is the relative molecular mass of the gas?

(G.M.V at s.t.p = 22.40dm³)

A28

B32

C44

D71

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Question 15

jamb 1990

If a gas occupies a container of volume 146 cm3 at 18°C and 0.971 atm, its volume in cm3 at s.t.p is?

A133

B146

C266

D292

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Question 16

jamb 1990

Which of the following is formed when maltose reacts with concentrated tetraoxosulphate (VI) acid ?

ACarbon (IV) oxide

BCoal tar

CCharcoal

DToxic fumes

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Question 17

jamb 1990

The octane number of a fuel whose performance is the same as that of a mixture of 55 g of 2,2,4- trimethly pentane and 45 g of n-heptane is ?

A45

B55

C80

D100

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Question 18

jamb 1990

Alkaonic acids have low volatility compared with alkanols because they?

Aare more polar than alkaonls

Bhave two oxygen atoms while alkanols have one

Cform hydrogen bonds while alkanols do not

Dform two hydrogen bonds while alkanols form one

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Question 19

jamb 1990

The label on a reagent bottle containing a clear organic liquid dropped off.The liquid was neutral to litmus and gave a colourless gas with metallic sodium. The liquid must be an?

Aalkanoate

Balkaene

Calkanol

Dalkane

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Question 20

jamb 1990

A cycloalkane with the molecular formula C5H10 has ?

Aone isomer

Btwo isomers

Cthree isomers

Dfour isomers

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Question 21

jamb 1990

Which of the following compounds gives a yellow residue when heated and also reacts with aqueous sodium hydroxide to give a white gelatinous precipitate soluble in excess sodium hydroxide solution?

A(NH₄)CO₃

BZnCO₃

CAl₂(SO₄)₃

DPbCO3

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Question 22

jamb 1990

To make coloured glasses, small quantities of oxides of metals which form coloured silicates are often added to the reaction mixture consisting of Na₂CO₃ and SiO₂. Such a metals is a?.

Apottasium

Bbarium

Czinc

Dcopper

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Question 23

jamb 1990

Sodium hydroxide should be stored in properly closed containers because it?

Areadily asborbs water vapour to air

Bis easily oxidize by atmospheric oxygen

Cturns golden yellow when exposed to light

Dmelts at a low temperature

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Question 24

jamb 1990

The major component of the slag from the production of iron is?

Aan alloy of calcium and iron

Bcoke

Cimpure iron

Dcalcium trioxosilicate (IV)

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Question 25

jamb 1990

Coal fire should not be used in poorly ventilated rooms because ?

Aof the accumulation of CO₂ which causes dep sleep

Bit is usually too hot

Cof the acumulation of CO which causes suffocation

Dit removes most most of the gases in the rooms

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Question 26

jamb 1990

Which of the following metals will liberate hydrogen from steam or dilute acid?

ACopper

BIron

CLead

DMercury

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Question 27

jamb 1990

A metallic oxide which reacts with both HCl and NaOH to give salt and water only can be classified as?

Aan acidic oxide

Ba basic oxide

Ca neutral oxide

Dan amphoteric oxide

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Question 28

jamb 1990

In the Haber process for the manufacture of ammonia, the catalyst commonly used is finely divided ?

Avanadium

Bplatinum

Ciron

Dcopper

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Question 29

jamb 1990

Which of the following tests will completely identify anyone of surphur (VI) oxide, hydrogen, carbon (IV) oxide and nitrogen (II) oxide?

APass each gas into water and test with blue litmus paper

BPass each gas into lime water

CExpose each gas to atmospheric air

DPass each gas to concentrated tetraoxosulphate (IV) acid

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Question 30

jamb 1990

The brown fumes given off when trioxonitrate (V) acid is heated consist of ?

ANO₂ and O₂

BH₂O and NO₂

CNO_2' O₂ and H₂O

DNO, NO₂ and H₂O

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