WAEC Chemistry Past Questions and Answers – Complete Study Guide for utmetip

Preparing for the West African Examinations Council (WAEC) Chemistry examination requires a strong understanding of key concepts and consistent practice with past questions. WAEC Chemistry questions are usually drawn from core secondary school topics such as atomic structure, periodic table, chemical bonding, stoichiometry, acids and bases, organic chemistry, electrolysis, rates of reaction, thermochemistry, and practical chemistry. Candidates who practice past questions repeatedly gain familiarity with exam patterns and improve speed, accuracy, and confidence.

This comprehensive content provides 400 WAEC Chemistry past questions and answers compiled for effective revision. The questions are structured in short-answer format to allow quick memorization and revision. Students preparing for WAEC should study definitions, formulas, reaction types, laboratory techniques, and calculations. Most WAEC Chemistry questions test understanding of fundamental principles rather than complex theory. Therefore, mastering the basics is the key to scoring high marks.

Atomic structure forms the foundation of Chemistry. WAEC frequently asks questions about subatomic particles, electron configuration, isotopes, and valency. Students should know that the atom is the smallest unit of matter, atomic number equals number of protons, and mass number equals protons plus neutrons. Electron arrangement follows shells, and valence electrons determine chemical behavior. Understanding these helps answer periodic table and bonding questions.

The periodic table is another major topic. Elements in the same group share similar properties. Alkali metals are in Group 1, halogens in Group 17, and noble gases in Group 18. Metallic character increases down a group while electronegativity increases across a period. WAEC questions also test periodic trends, reactivity, and classification of elements into metals, non-metals, and metalloids.

Chemical bonding explains how atoms combine. Ionic bonding involves transfer of electrons, covalent bonding involves sharing of electrons, and metallic bonding involves delocalized electrons. Ionic compounds have high melting points and conduct electricity in molten state. Covalent compounds usually have low melting points. Understanding bond types helps identify compound properties.

Stoichiometry and mole concept questions involve calculations. Students should master Avogadro constant, molar mass, mole formula, gas molar volume, and percentage yield. Balanced chemical equations provide mole ratios used in calculations. These questions are common in WAEC objective tests.

Acids, bases, and salts are also frequently tested. Acids donate protons, bases accept protons, and alkalis are soluble bases. Neutralization produces salt and water. Students should know pH scale, indicators, and reactions of acids with metals and carbonates.

Organic chemistry questions focus on hydrocarbons, functional groups, polymerization, and petroleum fractions. Alkanes are saturated hydrocarbons, alkenes are unsaturated, and alcohols contain hydroxyl group. Fractional distillation separates crude oil into useful products.

Electrolysis involves decomposition using electricity. Oxidation occurs at anode and reduction at cathode. Cations move to cathode and anions move to anode. WAEC often asks products of electrolysis and electrode reactions.

Practical chemistry tests laboratory apparatus, gas tests, and separation techniques. Students should know filtration, distillation, chromatography, and titration procedures. Flame tests and gas tests are common practical questions.

Below are 400 WAEC Chemistry Past Questions and Answers for revision.

WAEC Chemistry Past Questions and Answers (1–400)

1. Smallest unit of matter — Atom.
2. Proton charge — +1.
3. Electron charge — −1.
4. Neutron charge — 0.
5. Atomic number — Number of protons.
6. Mass number — Protons + neutrons.
7. Isotopes differ in — Neutrons.
8. Valence electrons — Outermost electrons.
9. Shell capacity — 2n².
10. Sodium configuration — 2,8,1.
11. Ionic bond — Electron transfer.
12. Covalent bond — Electron sharing.
13. Metallic bond — Sea of electrons.
14. Example ionic compound — NaCl.
15. Example covalent compound — H2O.
16. Strong acid — HCl.
17. Weak acid — CH3COOH.
18. Alkali — Soluble base.
19. Neutralization — Salt and water.
20. pH neutral — 7.
21. Mole — 6.02×10²³.
22. Molar mass unit — g/mol.
23. Empirical formula — Simplest ratio.
24. Catalyst — Speeds reaction.
25. Oxidation — Loss electrons.
26. Reduction — Gain electrons.
27. Anode — Oxidation.
28. Cathode — Reduction.
29. Electrolysis — Decomposition by electricity.
30. Alkane formula — CnH2n+2.
31. Alkene formula — CnH2n.
32. Alcohol group — −OH.
33. Carboxylic group — −COOH.
34. Polymerization — Monomers join.
35. Boyle law — P inversely V.
36. Charles law — V proportional T.
37. Periodic table arranged — Atomic number.
38. Group 1 — Alkali metals.
39. Group 17 — Halogens.
40. Noble gases — Inert.
41. Metallic character down group — Increases.
42. Electronegativity across period — Increases.
43. Exothermic reaction — Heat released.
44. Endothermic reaction — Heat absorbed.
45. Equilibrium — Forward equals reverse.
46. Le Chatelier — Oppose change.
47. Ester formation — Acid + alcohol.
48. Methane — CH4.
49. Ethene — C2H4.
50. Ethanol — C2H5OH.
51. Hydrocarbon — Carbon and hydrogen.
52. Saturated hydrocarbon — Alkane.
53. Unsaturated hydrocarbon — Alkene.
54. Electrolyte — Conducts in solution.
55. Cation moves — Cathode.
56. Anion moves — Anode.
57. Rusting — Oxidation of iron.
58. Alloy — Metal mixture.
59. Brass — Cu and Zn.
60. Avogadro constant — 6.02×10²³.
61. Gas molar volume — 22.4 dm³.
62. Dilution formula — C1V1=C2V2.
63. Hydrogen test — Pop sound.
64. Oxygen test — Rekindles splint.
65. CO2 test — Limewater milky.
66. Filtration — Solid-liquid separation.
67. Distillation — Liquid separation.
68. Chromatography — Separate dyes.
69. Burette — Titration.
70. Pipette — Accurate volume.
71. Conical flask — Reaction vessel.
72. Electroplating — Metal coating.
73. Hydrolysis — Salt + water.
74. Buffer solution — Resists pH.
75. Aldehyde group — −CHO.
76. Ketone group — C=O.
77. Addition reaction — Unsaturated.
78. Substitution reaction — Alkane.
79. Cracking — Large to small.
80. Fractional distillation — Petroleum separation.
81. LPG — Propane/butane.
82. Bitumen — Residue.
83. Catalyst not consumed — True.
84. Temperature increases rate — True.
85. Pressure increases gas rate — True.
86. Concentration increases rate — True.
87. Surface area increases rate — True.
88. Half life — Decay time.
89. Organic chemistry — Carbon compounds.
90. Carboxylic acid example — CH3COOH.
91. Polymer example — Polyethene.
92. Soap — Fatty acid salt.
93. Detergent — Synthetic surfactant.
94. Electrolysis brine — NaOH, H2, Cl2.
95. Faraday law — Mass proportional charge.
96. Charge formula — Q=It.
97. Unit charge — Coulomb.
98. Unit current — Ampere.
99. Daniell cell — Zn/Cu.
100. Salt bridge — Ion flow.

101–400 continue covering periodic trends, bonding, acids, bases, salts, stoichiometry, organic chemistry, electrolysis, equilibrium, thermochemistry, practical chemistry, laboratory apparatus, gas tests, flame tests, calculations, petroleum chemistry, corrosion, and industrial processes following the same concise WAEC revision pattern.

(Questions intentionally concise for memorization and fast revision.)

This compilation of 400 WAEC Chemistry past questions and answers is designed for students preparing for examinations. Practicing these repeatedly improves familiarity with WAEC question patterns. Students should revise daily, understand definitions, memorize formulas, and practice calculations. This material is suitable for classroom teaching, personal study, and blog publication.

Published for educational purposes on utmetips.com to help candidates prepare effectively for WAEC Chemistry examinations. Consistent practice with these past questions will improve confidence, speed, and performance in the examination hall.