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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

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Question 771

waec 2012

Which of the following devices function on redox reaction? l. Dry cell ll. Car battery III. Electric generator

Al and lll only

Bll and lll only

Cl and ll only

Dl, ll and lll

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Question 772

waec 2012

Consider the reaction represented by the following equation: CuO\(_{(s)}\) + H\(_2\)SO\(_{4(aq)}\) → CuSO\(_{4(aq)}\) + H\(_2\)O\(_{(l)}\). Which of the following factors will not affect the rate of the reaction?

AParticle size of CuO_(s)

BConcentration of H₂SO_4(aq)

CTemperature of the reacting mixture

DPressure of reaction system

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Question 773

waec 2012

A spot of oil paint on a shirt can best be removed using?

Abrine

Bdetergent

Ckerosine

Dwarm water

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Question 774

waec 2012

The hydrolysis of NH\(_4\)CI gives

Aan acidic solution

Ban alkaline solution

Ca buffer solution

Da neutral solution

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Question 775

waec 2012

Which of the following pH values indicates that a solution is a strong base?

D13

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Question 776

waec 2012

On heating, the following trioxocarbonate (IV) salts decompose to give solid residue except

Aammonium trioxocarbonate (IV)

Bcalcium trioxocarbonate (IV)

Clead (ll) trioxocarbonate(IV)

Dzinc trioxocarbonate (IV)

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Question 777

waec 2012

A substance L reacts with NH\(_4\)NO\(_{3(aq)}\) to generate ammonia gas. L is likely to be

AHCl

BNaOH

CCH₃COOH

DCaSO₄

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Question 778

waec 2012

The energy evolved when magnesium burns in air is in the form of

Aheat

Bheat and sound

Clight and heat

Dsound

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Question 779

waec 2012

Which of the following gases has the lowest rate of diffusion under the same condition? [H = 1.00; He = 4. 00; O = 16.0; CI = 35.5]

ACI₂

BH₂

CHe

DO₂

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Question 780

waec 2012

The postulate that molecules are in constant random motion best explains why liquids

Acan undergo solidification

Bmaintain their volumes

Care incompressible

Dhave no characteristic shape

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Question 781

waec 2012

At ordinary temperature H\(_2\)O is a liquid while H\(_2\)S is a gas. This is because H\(_2\)O has

Aweak intermolecular forces holding its molecules together

Bstrong hydrogen bonds holding its molecules together

Cinduced dipole-induced dipole forces between its molecules

Dionic force between its molecules

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Question 782

waec 2012

When a substance changes directly from the solid state to the gaseous state without forming a liquid, the substance is said to

Acondense

Bevaporate

Csublime

Dprecipitate

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Question 783

waec 2012

The volume occupied by 0.4 g of hydrogen gas at s.t.p. is [H = 1. 00; Molar volume at s.t.p. = 22.4 dm3]

A2.24 dm³

B4.48dm³

C22.4dm³

D44.8dm ³

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Question 784

waec 2012

Which of the following metals would readily displace hydrogen from steam?

ACopper

BLead

CMagnesium

DSilver

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Question 785

waec 2012

A metal M forms two types of chlorine, MCl\(_2\) and MCl\(_3\) which of the following laws best explains the relationship between the chlorides? Law of

Aconservation of mass

Bdefinite proportion

Cmultiple proportion

Dreciprocal proportion

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Question 786

waec 2012

A sample of a gas may be identified as chlorine if it turns

Adamp blue litmus paper red

Blime water miky

Clead ethanoate paper black

Dstarch iodide paper blue-black

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Question 787

waec 2012

The formula of mercury (l) dioxonitrate (III) is

AHgNO₃

BHg₂NO₂

CHg₂(NO₂)₂

DHg(NO₃)₂

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Question 788

waec 2012

Consider the reaction represented by the following equation: xCH\(_3\)OH + yO\(_2\) → 2CO\(_2\) + zH\(_2\)O. The values of x,y and z respectively, are

A2,3 and 4

B2, 4 and 3

C1,2 and 3

D1, 3 and 5

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Question 789

waec 2012

The number of sulphur atoms in 3.20g of SO\(_{2(g)}\) is [O = 16.0;S = 32.0; Avogadro c x 10\(^{23}\)]

A3.01 x 10²²

B6.02 x 10²²

C6.02 x10²³

D1.20 x 10²⁴

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Question 790

waec 2012

Consider the following reaction equation: CaCO\(_{3(s)}\) + 2HCI\(_{(aq)}\) → CaCl\(_{2(aq)}\) + H\(_2\)O\(_{(l)}\) + CO\(_{2(g)}\). What mass of CaCI\(_2\) would be obtained when 25.0g of CaCO\(_{3(s)}\) is reacted with excess HCI\(_{(aq)}\)? [CaCO\(_3 = 100; CaCI\(_2\) = 111]

A4.00g

B4.44 g

C18.9 g

D27.8 g

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