Classroom

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

Select subject

Download PHP app Ask a Question Check Syllabus Past Question Videos Topic Video Lessons

Take a test

Custom CBT

Create and set up a CBT environment with your preferred subjects.

JAMB CBT Simulator

Practice JAMB CBT with real UTME past questions in CBT format.

WAEC CBT Practice 2026 Simulator

CB-WASSCE styled past question practice.

NECO CBT Practice 2026 Simulator

SSCE & GCE styled past question practice.

Past Questions

4,306 questions

Question 1 of 20 4,306 total questions

Question 1621

jamb 1995

Helium is often used in observation balloons because it is?

Alight and combustible

Blight and non-combustible

Cheavy and combustible

Dheavy and non-combustible

View Explanation & Discuss

Question 1622

jamb 1995

Which of the following statements is FALSE about isotopes of the same element?

AThey have the same number of electrons in their outermost shells

BThey have different atomic masses

CThey have the same atomic number and the number of electrons

DThey have the same atomic number but different number of electrons

View Explanation & Discuss

Question 1623

jamb 1995

The ability of ionic solids is generally due to the?

Anegative electron affinity of most atoms

Bcrystal lattice forces

Celectron pair sharing

Dpositive ionization potentials

View Explanation & Discuss

Question 1624

jamb 1995

In the oil drop experiment, Millikan determined the?

Acharge to mass ratio of the electron

Bmass of the electron

Ccharge of the electron

Dmass of the proton

View Explanation & Discuss

Question 1625

jamb 1995

A particle that contains 8 proton, 9 neutrons and 7 electrons could be written as?

BO⁺

DO^-

View Explanation & Discuss

Question 1626

jamb 1995

A liquid begins to boil when?

Aits vapour pressure is equal to the vapour pressure of its solid at the given temperature

Bmolecules start escaping from its surface

Cits vapour pressure equals the atmosphere pressure

Dits volume is sightly increased

View Explanation & Discuss

Question 1627

jamb 1995

Two cylinders A and B each contains 30 cm\(^3\) of oxygen and nitrogen respectively at the same temperature and pressure. If there are 5.0 moles of nitrogen, then the mass of oxygen is?

A3.2 g

B6.4 g

C80.0 g

D160.0 g

View Explanation & Discuss

Question 1628

jamb 1995

A gas sample with an initial volume of 3.25 dm³ is heated and allowed to expand to 9.75 dm³ at constant pressure. What is the ratio of the final absolute temperature to the initial absolute temperature?

A3:1

B5:2

C5:4

D8:3

View Explanation & Discuss

Question 1629

jamb 1995

What volume of oxygen will remain after reacting 8cm\(^3\) of hydrogen with 20cm\(^3\) of oxygen?

A10 cm³

B12 cm³

C14 cm³

D16 cm³

View Explanation & Discuss

Question 1630

jamb 1995

The number of hydrogen ions in 4.9 g of tetraoxosulphate (IV) acid is?

(S = 32, O =16, H = 1, Avogadro Number = 6.02 x 10\(^{23}\) )

A3.01 x 10²²

B6.02 x 10²²

C3.01 x 10²³

D6.01 x 10²³

View Explanation & Discuss

Question 1631

jamb 1995

Which of the following is a example of a chemical change?

ADissoultion of salt in water

BRusting of iron

CMelting of ice

DSeparating a mixture by distillation

View Explanation & Discuss

Question 1632

jamb 1995

Chromatography is used to separate components of mixtures which differ in their rates of?

Adiffusion

Bmigration

Creaction

Dsedimentaion

View Explanation & Discuss

Question 1633

waec 1994

What is the molar mass of an alkyne with the formula C_x H ₁₄? (H = 1, C = 12)

A86g

B92g

C98g

D110g

E112g

View Explanation & Discuss

Question 1634

waec 1994

The following compounds contain the same type of bonds except

Asodium chloride

Bhydrogen chloride

Cmagnesium chloride

Dpotassium chloride

Elithium chloride

View Explanation & Discuss

Question 1635

waec 1994

When magnesium ribbon burns in air, the products are

Amagnesium nitride and magnesium oxide

Bmagnesium nitride and carbon (ll) oxide

Cmagnesium oxide and steam

Dmagnesium nitride and soot

Emagnesium oxide and carbon (ll) oxide

View Explanation & Discuss

Question 1636

waec 1994

Destructive distillation of coal means

Aheating coal in plentiful supply of air

Bburning coal in air to produce water and carbon (IV) oxide

Cheating coal in the absence of air

Dheating coal in limited supply of air

Eseparating coal into various allotropes of carbon

View Explanation & Discuss

Question 1637

waec 1994

Study the reaction represented by the equation: Alkanol + Alkanoic acid + conc. H\(_2\)SO\(_4\) → Alkanoate + water. The type of process involved in the reverse reaction is

ANeutralization

Bdehydration

Chydrolysis

Ddecomposition

Ehydrogenation

View Explanation & Discuss

Question 1638

waec 1994

Which of the following is likely to have the highest degree of hardness?

ACarbonated water

BDistilled water

CAcidified water

DRain water

ELime water

View Explanation & Discuss

Question 1639

waec 1994

Which of the following is not a halogen?

ASilicon

BFluorine

CAstatine

DBromine

Elodine

View Explanation & Discuss

Question 1640

waec 1994

The gaseous product formed when ammonia is passed over heated copper (ll) oxide is

Aoxygen

Bnitrogen

Chydrogen

Dnitrogen (l) oxide

Enitrogen (ll) oxide

View Explanation & Discuss

Question Navigator

Current

Chemistry Past Questions

Take a test

Custom CBT

JAMB CBT Simulator

WAEC CBT Practice 2026 Simulator

NECO CBT Practice 2026 Simulator

Past Questions

Question Navigator

MathsFaculty