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

Take a test

Past Questions

4,306 questions
Question 1 of 20 4,306 total questions
Question 231
jamb 2023

What is the molar mass of water (H2O)?

A18 g/mol
B22 g/mol
C16 g/mol
D12 g/mol
View Explanation & Discuss
Question 232
jamb 2023

Which organic compound is responsible for the characteristic aroma of fruits?

AAlkane
BAlkyne
CEster
DAmine
View Explanation & Discuss
Question 233
jamb 2023

Which of the following factors does NOT affect the rate of a chemical reaction?

AConcentration of reactants
BPresence of a catalyst
CMolecular weight of products
DTemperature
View Explanation & Discuss
Question 234
jamb 2023

When an acidic solution is diluted, what happens to its pH?

AIt depends on the specific acid
BIt decreases
CIt remains the same
DIt increases
View Explanation & Discuss
Question 235
jamb 2023

What is the product of the electrolysis of aqueous sodium chloride (NaCl) using inert electrodes?

AHydrogen gas at the cathode and chlorine gas at the anode
BHydrogen gas at the cathode and oxygen gas at the anode
CSodium metal at the cathode and chlorine gas at the anode
DSodium metal at the cathode and oxygen gas at the anode
View Explanation & Discuss
Question 236
jamb 2023

Which of the following alkanes has a straight-chain structure?

ACyclopentane (C5H10)
BIsobutane (C4H10)
C2 - methyl propane (C4H10)
DPentane (C5H12)
View Explanation & Discuss
Question 237
jamb 2023

Which type of chemical combination involves the transfer of electrons from one atom to another, resulting in the formation of oppositely charged ions?

AIonic bonding
BHydrogen bonding
CCovalent bonding
DMetallic bonding
View Explanation & Discuss
Question 238
jamb 2023

What is the trend for ionization energy across a period in the periodic table?

AIncreases from left to right.
BRemains constant
CVaries randomly
DDecreases from left to right
View Explanation & Discuss
Question 239
jamb 2023

Balance the following redox reaction:
Fe\(_2\)O\(_3\) + CO → Fe + CO\(_2\)

AFe\(_2\)O\(_3\) + CO → 2Fe + 2CO\(_2\)
B2Fe\(_2\)O\(_3\) + 3CO → 4Fe + 3CO\(_2\)
CFe\(_2\)O\(_3\) + 2CO → 2Fe + 2CO\(_2\)
DFe\(_2\)O\(_3\) + 3CO → 2Fe + 3CO\(_2\)
View Explanation & Discuss
Question 240
jamb 2023

Identify the reducing agent in the following reaction:
Zn + CuSO\(_4\) → ZnSO\(_4\) + Cu

ACu
BZn
CZnSO\(_4\)
DCuSO\(_4\)
View Explanation & Discuss
Question 241
jamb 2023

What is the state of matter in which particles are widely spaced and move freely with high kinetic energy?

ALiquid
BSolid
CPlasma
DGas
View Explanation & Discuss
Question 242
jamb 2023

Stainless steel is an alloy made up of

AIron and zinc
BCopper and tin
CIron and chromium
DIron and carbon
View Explanation & Discuss
Question 243
jamb 2023

A gas occupies a volume of 1.5 liters at a pressure of 2 atmospheres. If the pressure is increased to 4 atmospheres while the temperature remains constant, what will be the new volume of the gas?

A6 liters
B1.5 liters
C0.75 liters
D3 liters
View Explanation & Discuss
Question 244
jamb 2023

What is Faraday's constant?

A6.022 x 10\(^{23}\) mol\(^{-1}\)
B3.00 x 10\(^8\) m/s
C9.81 m/s\(^2\)
D96,485 C/mol
View Explanation & Discuss
Question 245
jamb 2023

Which of the following methods can be used to remove temporary hardness from water?

ABoiling
BFiltration
Csedimentation
DChlorination
View Explanation & Discuss
Question 246
jamb 2023

Which trace gas in the atmosphere plays a significant role in the greenhouse effect?

AOxygen
BArgon
CCarbon dioxide
DNitrogen
View Explanation & Discuss
Question 247
jamb 2023

What is the solubility product constant (Ksp) used for?

ATo measure the total mass of a solute that can dissolve in a solvent
BTo determine the concentration of a solute in a saturated solution
CTo calculate the solubility of a solute in a given solvent
DTo compare the solubilities of different solutes in the same solvent
View Explanation & Discuss
Question 248
jamb 2023

What is the chemical structure of soap and detergent molecules?

AHydrophilic head and hydrophobic tail
BHydrophilic head and hydrophilic tail
CHydrophobic head and hydrophobic tail
DHydrophilic tail and hydrophobic head
View Explanation & Discuss
Question 249
jamb 2023

What happens to the value of the equilibrium constant (Kc) for a reaction if the reaction is reversed?

AIt becomes zero
BIt becomes negative
CIt remains the same
DIt becomes the reciprocal of the original value
View Explanation & Discuss
Question 250
jamb 2023

Which of the following is an example of an endothermic reaction?

ACombustion of propane (C\(_3\)H\(_8\)) to produce carbon dioxide (CO\(_2\)) and water (H\(_2\)O).
BBurning of methane (CH\(_4\)) in the presence of oxygen
CFormation of table salt (NaCl) from sodium (Na) and chlorine (Cl\(_2\)).
DDecomposition of hydrogen peroxide (H\(_2\)O\(_2\)) into water (H\(_2\)O) and oxygen (O\(_2\)).
View Explanation & Discuss
Question Navigator
Current
MathsFaculty