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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 771

jamb 1999

What quantity of electricity will liberate 0.125 mole of oxygen molecules during the electrolysis of dilute sodium chloride solution?
[ F = 96 5000 C mol^-1 ]

A24 125 coulombs

B48 250 coulombs

C72 375 coulombs

D96 500 coulombs

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Question 772

jamb 1999

N\(_2\)O\(_4\)(g) ↔ 2NO\(_2\)(g). Increase in total pressure of the equilibrium reaction above will

Aproduce more of NO_2(g) in the mixture

Bconvert all of N₂O_4(g) to NO_2(g)

Chave no effect on the concentrations of NO_2(g)and N₂O_4(g)

Dproduce more of N₂O_4(g) in the mixture

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Question 773

jamb 1999

2SO_2(g) + O_2(g) ↔ 2SO_3(g). In the chemical reaction above, the substance that will increase the rate of production of sulphur (VI) oxide is

Amanganese (IV) oxide

Bfinely divided iron

Cvanadium (V) oxide

Dnickel

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Question 774

jamb 1999

The entropy and enthalpy of a system are a measure of

Adegree of disorderlinesss and heat content respectively

Bheat content and degree of disorderliness respectively

Cheat content of a system only

Ddegree of disorderliness only

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Question 775

jamb 1999

The solubility product of Cu(IO3)2 is 1.08 * 10-7. Assuming that neither ions react appreciable with water to form H+ and OH-, what is the solubility of this salt?

A2.7 * 10^-8 mol dm^-3

B9.0 * 10^-8 mol dm^-3

C3.0 * 10^-3 mol dm^-3

D9.0 * 10^-3 mol dm^-3

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Question 776

jamb 1999

The solution with the lowest pH value is

A5 ml of (m/10) HCl

B10 ml of (m/10) HCl

C15 ml of (m/5) HCl

D20 ml of (m/8) HCl

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Question 777

jamb 1999

What is observed when aqueous solutions of each of tetraoxosulphate (VI) acid, potassium trioxoiodate (V) and potassium iodide are mixed together?

AA white precipitate is formed

BA green precipitate is formed

CThe mixture remains colourless

DThe mixture turns reddish brown

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Question 778

jamb 1999

The set of pollutants that is most likely to be produced when petrol is accidentally spilled on plastic materials and ignited is

ACO, CO² and SO²

BCO, HCL and SO²

CCO, CO² and HCL

DSO², CO² and HCL

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Question 779

jamb 1999

The correct order of increasing oxidation number of the transition metal ions for the compounds K₂Cr₂O₇, V₂O₅ and KMnO₄ is

AV₂O₅ < K₂Cr₂O₇ < KMnO₄

BK₂Cr₂O₇ < KMnO₄ < V₂O₅

CKMnO₄ < K₂Cr₂O₇ < V₂O₅

DKMnO₄ < V₂O₅ < K₂Cr₂O₇

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Question 780

jamb 1999

0.25 mole of hydrogen chloride was dissolved in distilled water and the volume made up of 0.50 dm³. If 15.0 cm³ of the solution requires 12.50 cm³ of aqueous sodium trioxocarbonate (IV) for neutralization, calculate the concentration of the alkaline solution

A0.30 mol dm³

B0.40 mol dm³

C0.50 mol dm³

D0.60 mol dm³

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Question 781

jamb 1999

Given that electronegativity increases across a period and decreases down a group in the periodic table, in which of the following compounds will the molecules be held together by the strongest hydrogen bond?

AHF_(g)

BNH_3(g)

CCH_4(g)

DHCl_(g)

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Question 782

jamb 1999

1s², 2s², 2p⁶, 3s², 3p⁶, 3d⁷, 4s²
An element with the electronic configuration above is a

Anon-metal

Bmetal

Ctransition element

Dgroup two element

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Question 783

jamb 1999

The method that can be used to convert hard water to soft water is

Achlorination

Bpassage over activated charcoal

Cthe use of an ion-exchange resin

Daeration

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Question 784

jamb 1999

Nitrogen obtained from the liquefaction of air has a higher density than that obtained from nitrogen containing compounds because the former contains

Awater vapour

Boxygen

Ccarbon (IV) oxide

Drare gases

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Question 785

jamb 1999

In order to remove one electron from a 3S orbital of gaseous sodium atom, about 496KJMol^-1 of energy is required. This energy is referred to as

Aelectron affinity

Bionization energy

Cactivation evergy

Delectronegativity

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Question 786

jamb 1999

In which of the following are water molecules in the most disorderly arrangement?

AIce at -10°C

BIce at 0°C

CWater at 100°C

DSteam at 100°C

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Question 787

jamb 1999

A gaseous metallic chloride MClx consists of 20.22% of M by mass. The formula of the chloride is?
[M = 27, Cl = 35.5]

AMCl

BMCl₂

CMCl₃

DM₂Cl₆

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Question 788

jamb 1999

Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)
From the equation above, the mass of magnesium required to react with 250cm3 of 0.5M HCl is
[Mg = 24]

A0.3g

B1.5g

C2.4g

D3.0g

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Question 789

jamb 1999

Which of the following will have its mass increased when heated in air?

AHelium

BMagnesium

CCopper pyrites

DGlass

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Question 790

jamb 1999

Which is the temperature of a given mass of a gas initially at 0°C and 9 atm, if the pressure is reduced to 3 atm at constant volume?

A91K

B182K

C273K

D819K

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