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Chemistry Past Questions

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88 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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88 questions

Question 1 of 20 88 total questions

Question 11

waec 1994

If the volume of a given mass of gas at 0^oC is 27.3cm³, what will be the volume of the gas at 10^oC, pressure remaining constant?

A2.73cm³

B28.3cm³

C37.3cm³

D273cm³

E283cm³

View Explanation & Discuss

Question 12

waec 1994

Which of the following occurs when an aqueous solution of sodium hydroxide is electrolysed using graphite electrodes?

ASodium metal is produced at the anode

BSodium amalgam is formed at the cathode

COxygen gas is produced at the anode

DThe grahite anode dissolves

EThe resulting solution becomes acidic

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Question 13

waec 1994

When naphthalene on heating changes from the solid state directly to the gaseous state it undergoes

Aevaporation

Bsublimation

Cdecomposition

Dcombustion

Eionisation

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Question 14

waec 1994

Calcium is usually extracted by the electrolysis of its

Atrioxonitrate (V)

Btetraoxosulphate (IV)

Coxide

Dhydride

Echloride

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Question 15

waec 1994

Polyatomicity is illustrated by molecules of

Asulphur

Bcarbon (IV) oxide

Cnoble gases

Dliquefied oxygen

Eliquefied nitrogen

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Question 16

waec 1994

The following will decolourize acidified potassium tetraoxomanganate (VII) solution except

Asulphur (lV) oxide

Bbut-3-ene

Cpentane

Dhydrogen sulphide

Epropyne

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Question 17

waec 1994

Tetraoxosulphate (lV) acid is described as strong acid because it is highly

Acorrosive

Bconcentrated

Creactive

Dsoluble in water

Eionized in water

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Question 18

waec 1994

The number of atoms in 1.2g of carbon - 12 isotope is

A1.00 x 10 ₂₂

B6.02 x 10₂₂

C1.20 x 10 ₂₃

D1.00 x 10₂₃

E6.02 x 10₂₄

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Question 19

waec 1994

The oxidation number of phosphorus in \(PO_4^{3-}\) is

A+ 1

B+2

C+3

D+4

E+5

View Explanation & Discuss

Question 20

waec 1994

Which of the following would increase the rate of reaction of chips of a metal M as shown in the equation below? M_(s) + 2HCI_(aq) → MCI_2(aq) + H_2(g)

ADiluting the hydrochloric acid

BAdding some distilled water

CDecreasing the temperature

DGrinding the metal into powder

EIncreasing the pressure

View Explanation & Discuss

Question 21

waec 1994

Which of the following is not a property of magnesium oxide?

AHigh melting point

BDissolution in polar solvents

CPresence of ionic bonds

DPossession of crystal lattice

ELow binding energy

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Question 22

waec 1994

In any chemical reaction, the total mass of the products is always equal to that of the reactants. This is statement of the law of

Adefinite proportion

Bconservation of matter

Cmultiple proportions

Dreciprocal proportions

Econstant composition

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Question 23

waec 1994

A measure of the degree of disorder in a chemical system is known as the

Aenthalpy

Bfree energy

Cactivation energy

Dentrophy

Eequilibrium

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Question 24

waec 1994

Catalytic hydrogenation of alkenes produces compounds with the general formula

AC_nH_2n+1 OH

BC_nH_2n+1

CC_nH_2n+2

DC_nH_2n-2

EC_x(H₂O)_y

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Question 25

waec 1994

The number of replaceable hydrogen atoms in one acid indicates its

Abasicity

Bacidity

Calkalinity

Dreactivity

EpH value

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Question 26

waec 1994

The components of universal indicator solution can best be separated by

Achromatography

Bfiltration

Cevaporation

Dcrystallization

Efractional distillation

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Question 27

jamb 1994

From the above diagram, the caustic soda in the conical flask serves to

Adry ethene gas

Bremove carbon (iv) oxides from ethene

Cremove carbon (ii) oxide from ethene

Dremove sulphur (iv) oxide from ethene

View Explanation & Discuss

Question 28

jamb 1994

When sodium ethanoate is treated with a few drops of concentrated tetraoxosulphate(vi)acid. one of the products is

ACH₃COOH

BCH₃COOCH₃

CCH₃COOC₂H₅

DC₂H₅COOCH₃

View Explanation & Discuss

Question 29

jamb 1994

Clothes should be properly rinsed with water after bleaching because

Athe bleach decolourizes the clothes

Bchlorine reacts with fabrics during bleaching

Cthe clothes are sterilized during bleaching

Dhydrogen chloride solution is produced during bleaching

View Explanation & Discuss

Question 30

jamb 1994

which of these metals CANNOT replace hydrogen from alkaline solutions?

AAluminium

BZinc

CTin

DIron

View Explanation & Discuss

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