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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.

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

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4,306 questions

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Question 351

waec 2020

The initial volume and pressure of a given mass of gas is V and 3.P. What is its pressure if its volume is increased to 2V at constant temperature?

A3 P

B2P

C\(frac{3}{2}\) P

D\(frac{2}{3}\) P

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Question 352

waec 2020

f 5.0 cm\(^-3\) of 0.200 mol dm(^-3\) Na\(_2\)CO\(_3\) was diluted to 250cm(^-3\) solution, what would be the concentration of the resulting solution?

A0.004 mol dm(^-3\)

B0.020 mol dm(^-3\)

C0.200 mol dm(^-3\)

D0.400 mol dm(^-3\)

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Question 353

waec 2020

Which of the following standard conditions is not correct about energy changes?

AStandard temperature is 298K

BB. Standard pressure is 1 atm

CConcentration of solution must be 1 mol/dm\(^3\)

DΔH at 298 K is the activation energy

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Question 354

waec 2020

Which of the following reactions are always exothermic? 1. Neutralization Il. Decomposition III. Combustion

AI and II only

BI and III only

CII and IIl only

DI, II and III

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Question 355

waec 2020

Which of the following statements is correet for a reaction at equilibrium?

AAll reactions cease to occur

BThe eaction has gone to completion

CThe rates of the forward and backward reactions are equal

DThe amount of product equals the amount of reactants

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Question 356

waec 2020

Which of the following substances is not a reducing agent?

BCO

CO\(_2\)

DH\(_2\)

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Question 357

waec 2020

Which of the following compounds would release hydrogen when reacted with sodium metal?

I. CH\(_3\)COOH

II. CH\(_3\)CH\(_2\)OH

III. CH\(_3\)COOCH\(_3\)

AI only

BI and II only

CIl and IIl only

DI and Ill only

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Question 358

waec 2020

An alkanol containing 60% carbon by mass would have a molecular formula [H=1.0. C-12.0, O= 16.0]

ACH\(_3\)OH

BC\(_2\)H\(_5\)OH

CC\(_3\)H\(_7\)OH

DC\(_4\)H\(_9\)OH

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Question 359

waec 2020

Which of the following compounds has the lowest boiling point?

AC\(_4\)H\(_10\)

BCH\(_3\)COOH

CH\(_2\)O

DC\(_2\)H\(_5\)OH

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Question 360

waec 2020

The type of isomerism exhibited by cis and trans isomers is?

Apositional

Bgeometrical

Cfunctional

Doptical

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Question 361

waec 2020

The following molecules have double covalent bonds between two atoms except?

Aoxygen

Bcarbon (IV)oxide

Cethene

Dwater

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Question 362

waec 2020

Which of the following solids would not decompose on heating?

AAmmonium chloride

BLead (i) trioxonitrate (V)

CPotassium trioxocarbonate (IV)

DSodium hydrogen trioxocarbonate (IV)

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Question 363

waec 2020

The boiling point of pentane is higher than that of propane because?

Acarbon-carbon single bonds are stronger than carbon-hydrogen bonds.

BPentane has more covalent bonds to break

CPentane does not burn easily as
propane

DThe intermolecular forces in pentane are stronger than those of propane

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Question 364

waec 2020

A factor that is considered most important when siting a chemical industry is?

Anearness to other industrial establishments

Bnearness to raw materials

Cfavourable climate conditions

Davailability of storage facilities

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Question 365

waec 2020

Which of the following pairs of elements has the greatest difference in electronegativity?

ANa and F

BNa and CI

CNa and Br

DNa and I

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Question 366

waec 2020

A balanced chemical equation is based on the law of?

APeriodicity

BConstant composition

CMultiple proportion

DConservation of mass

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Question 367

waec 2020

The oxidation state of chlorine in NaClO\(_3\) is?

A+1

B+3

C+5

D+6

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Question 368

waec 2020

When an ionic bond is broken, bonding electrons are

Ashared between participating atoms

Bgained by the most electropositive atom

Cgained by the most electronegative atom

Dlost by both participating atoms.

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Question 369

waec 2020

Group VIl elements in their combined states are called?

AHalogens

BAnions

CHalide

DCations

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Question 370

waec 2020

The most suitable process of obtaining water from an aqueous solution of sugar i

ACrystallization

BDistillation

CFiltration

DDecantation

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