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Chemistry Past Questions

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4,306 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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4,306 questions

Question 1 of 20 4,306 total questions

Question 1821

jamb 1990

A blue solid, T, which weighed 5.0g was placed on a table. After 8 hours, the resulting pink solid was found to weigh 5.5g. It can be inferred that substance T?

Ais deliquescent

Bis hygroscopic

Chas some molecules of water of crystallization

Dis efflorescent

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Question 1822

jamb 1990

10.0 dm³ of air containing H₂S as an impurity was passed through a solution of Pb(NO₃)₂ until all the H₂S had reacted. The precipitate of PbS was found to weigh 5.02 g. According to the equation:

Pb(NO₃)₂ + H₂S → PbS + 2HNO₃ the percentage by volume of hydrogen sulphide in the air is?

(Pb = 207, S = 32, GMV at s.t.p = 22.4dm³)

A50.2

B47.0

C4.70

D0.47

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Question 1823

jamb 1990

Chlorine, consisting of two isotopes of mass numbers 35 and 37, has an atomic mass of 35.5.
The relative abundance of the isotope of mass number 37 is?

A20

B25

C50

D75

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Question 1824

jamb 1990

X(g) → X\(^-\)(g). The type of energy involved in the above transformation is?

Aionization energy

Bsublimation energy

Clattice energy

Delectron affinity

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Question 1825

jamb 1990

Which of the following terms indicates the number of bonds that can be formed by an atom?

AOxidation number

BValence

CAtomic number

DElectronegativity

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Question 1826

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 1827

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 1828

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 1829

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 1830

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 1831

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 1832

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 1833

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 1834

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 1835

jamb 1990

A cycloalkane with the molecular formula C5H10 has ?

Aone isomer

Btwo isomers

Cthree isomers

Dfour isomers

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Question 1836

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 1837

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 1838

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 1839

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 1840

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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