2023 JAMB CHEMISTRY PAST QUESTIONS AND ANSWERS Leave a Comment / Jamb Chemistry / By Jamb Tutor Report a question What’s wrong with this question? You cannot submit an empty report. Please add some details. 0% 0 votes, 0 avg Created by Jamb TutorJamb Chemistry 2023 JAMB CHEMISTRY PAST QUESTIONS AND ANSWERS 1 / 45 Category: JAMB Chemistry 2023 1. $$\text{What happens to equilibrium position if temperature decreases in an exothermic reaction?}$$ a) $$\text{Left.}$$ b) $$\text{Right.}$$ c) $$\text{Unchanged.}$$ d) $$\text{Stops.}$$ $$\text{Equilibrium shifts right to favor heat production.}$$ 2 / 45 Category: JAMB Chemistry 2023 2. $$\text{Which radioactive noble gas forms as uranium and thorium decay?}$$ a) $$\text{Argon.}$$ b) $$\text{Krypton.}$$ c) $$\text{Radon.}$$ d) $$\text{Neon.}$$ $$\text{Radon is the noble gas produced during decay.}$$ 3 / 45 Category: JAMB Chemistry 2023 3. $$\text{Reaction with highest entropy change: Liquid } \rightarrow \text{ Gas, Solid } \rightarrow \text{ Liquid, etc.?}$$ a) $$\text{Liquid to Gas.}$$ b) $$\text{Solid to Liquid.}$$ c) $$\text{Gas to Liquid.}$$ d) $$\text{Gas to Solid.}$$ $$\text{Liquid to gas has maximum entropy increase.}$$ 4 / 45 Category: JAMB Chemistry 2023 4. $$\text{Sum of oxidation numbers in neutral compound?}$$ a) $$\text{+2.}$$ b) $$\text{-1.}$$ c) $$\text{0.}$$ d) $$\text{+1.}$$ $$\text{The total oxidation number for a neutral compound is always } 0.$$ 5 / 45 Category: JAMB Chemistry 2023 5. $$\text{Pressure by gases explained in kinetic theory?}$$ a) $$\text{Vibrations.}$$ b) $$\text{Weight of particles.}$$ c) $$\text{Attractive forces.}$$ d) $$\text{Collisions with walls.}$$ $$\text{Pressure arises from collisions with container walls.}$$ 6 / 45 Category: JAMB Chemistry 2023 6. $$\text{Eutrophication definition?}$$ a) $$\text{Harmful chemicals.}$$ b) $$\text{Algal growth.}$$ c) $$\text{Heavy metals.}$$ d) $$\text{Oil slicks.}$$ $$\text{Caused by nutrient over-enrichment, leading to algal blooms.}$$ 7 / 45 Category: JAMB Chemistry 2023 7. $$\text{Name of industrial process to produce ammonia?}$$ a) $$\text{Nitrogenation.}$$ b) $$\text{Ammoniation.}$$ c) $$\text{Nitrification.}$$ d) $$\text{Haber process.}$$ $$\text{Haber process synthesizes ammonia industrially.}$$ 8 / 45 Category: JAMB Chemistry 2023 8. $$\text{Scientist proposing planetary atomic model?}$$ a) $$\text{Schrödinger.}$$ b) $$\text{Rutherford.}$$ c) $$\text{Bohr.}$$ d) $$\text{Thomson.}$$ $$\text{Rutherford introduced the orbiting electrons model.}$$ 9 / 45 Category: JAMB Chemistry 2023 9. $$\text{Example of an endothermic reaction?}$$ a) $$\text{Burning methane.}$$ b) $$\text{NaCl formation.}$$ c) $$\text{H}_2\text{O}_2\text{ decomposition.}$$ d) $$\text{Combustion of propane.}$$ $$\text{Decomposition of H}_2\text{O}_2\text{ absorbs energy.}$$ 10 / 45 Category: JAMB Chemistry 2023 10. $$\text{Effect on K}_c\text{ value when reaction reverses?}$$ a) $$\text{Becomes 0.}$$ b) $$\text{Becomes negative.}$$ c) $$\text{Unchanged.}$$ d) $$\text{Reciprocal.}$$ $$\text{K}_c\text{ becomes reciprocal of the original value.}$$ 11 / 45 Category: JAMB Chemistry 2023 11. $$\text{Chemical structure of soap/detergent?}$$ a) $$\text{Hydrophilic head, hydrophobic tail.}$$ b) $$\text{Hydrophilic head, hydrophilic tail.}$$ c) $$\text{Hydrophobic head/tail.}$$ d) $$\text{Hydrophilic tail.}$$ $$\text{Hydrophilic head attracts water; hydrophobic tail repels it.}$$ 12 / 45 Category: JAMB Chemistry 2023 12. $$\text{Purpose of K}_\text{sp}\text{ constant?}$$ a) $$\text{Total mass dissolved.}$$ b) $$\text{Solute concentration.}$$ c) $$\text{Calculate solubility.}$$ d) $$\text{Compare solubility.}$$ $$\text{Measures solute concentration in saturated solutions.}$$ 13 / 45 Category: JAMB Chemistry 2023 13. $$\text{Atmospheric trace gas in greenhouse effect?}$$ a) $$\text{Oxygen.}$$ b) $$\text{Argon.}$$ c) $$\text{Carbon dioxide.}$$ d) $$\text{Nitrogen.}$$ $$\text{Carbon dioxide is a significant greenhouse gas.}$$ 14 / 45 Category: JAMB Chemistry 2023 14. $$\text{Method to remove temporary water hardness?}$$ a) $$\text{Boiling.}$$ b) $$\text{Filtration.}$$ c) $$\text{Sedimentation.}$$ d) $$\text{Chlorination.}$$ $$\text{Boiling removes bicarbonates causing temporary hardness.}$$ 15 / 45 Category: JAMB Chemistry 2023 15. $$\text{Value of Faraday’s constant?}$$ a) $$\text{6.022 × 10}^\text{23}\text{ mol}^{-1}.}$$ b) $$\text{3.00 × 10}^\text{8}\text{ m/s.}$$ c) $$\text{9.81 m/s}^\text{2}.}$$ d) $$\text{96,485 C/mol.}$$ $$\text{One mole of charge: } 96,485 \text{ C/mol.}$$ 16 / 45 Category: JAMB Chemistry 2023 16. $$\text{Gas volume change with pressure increase?}$$ a) $$\text{6 liters.}$$ b) $$\text{1.5 liters.}$$ c) $$\text{0.75 liters.}$$ d) $$\text{3 liters.}$$ $$\text{Halving the volume doubles the pressure per Boyle’s Law.}$$ 17 / 45 Category: JAMB Chemistry 2023 17. $$\text{Composition of stainless steel alloy?}$$ a) $$\text{Iron and zinc.}$$ b) $$\text{Copper and tin.}$$ c) $$\text{Iron and chromium.}$$ d) $$\text{Iron and carbon.}$$ $$\text{Iron alloyed with chromium resists rusting.}$$ 18 / 45 Category: JAMB Chemistry 2023 18. $$\text{State of matter with widely spaced, high-energy particles?}$$ a) $$\text{Liquid.}$$ b) $$\text{Solid.}$$ c) $$\text{Plasma.}$$ d) $$\text{Gas.}$$ $$\text{Gas particles exhibit high kinetic energy and freedom.}$$ 19 / 45 Category: JAMB Chemistry 2023 19. $$\text{Reducing agent in reaction: Zn + CuSO}_4 \rightarrow \text{ZnSO}_4 + \text{Cu}?$$ a) $$\text{Cu.}$$ b) $$\text{Zn.}$$ c) $$\text{ZnSO}_4\text{.}$$ d) $$\text{CuSO}_4\text{.}$$ $$\text{Zinc donates electrons, reducing Cu}^{2+}\text{ to Cu.}$$ 20 / 45 Category: JAMB Chemistry 2023 20. $$\text{Balance Fe}_2\text{O}_3 \text{ + CO} \rightarrow \text{Fe + CO}_2\text{.}$$ a) $$\text{Fe}_2\text{O}_3\text{ + CO} \rightarrow 2\text{Fe + 2CO}_2\text{.}$$ b) $$\text{2Fe}_2\text{O}_3\text{ + 3CO} \rightarrow 4\text{Fe + 3CO}_2\text{.}$$ c) $$\text{Fe}_2\text{O}_3\text{ + 2CO} \rightarrow 2\text{Fe + 2CO}_2\text{.}$$ d) $$\text{Fe}_2\text{O}_3\text{ + 3CO} \rightarrow 2\text{Fe + 3CO}_2\text{.}$$ $$\text{Proper balancing satisfies stoichiometric laws.}$$ 21 / 45 Category: JAMB Chemistry 2023 21. $$\text{Trend of ionization energy across a period?}$$ a) $$\text{Increases left-right.}$$ b) $$\text{Constant.}$$ c) $$\text{Random variation.}$$ d) $$\text{Decreases left-right.}$$ $$\text{Ionization energy increases due to effective nuclear charge.}$$ 22 / 45 Category: JAMB Chemistry 2023 22. $$\text{Transfer of electrons forming oppositely charged ions?}$$ a) $$\text{Ionic.}$$ b) $$\text{Hydrogen.}$$ c) $$\text{Covalent.}$$ d) $$\text{Metallic.}$$ $$\text{Ionic bonds result from electron transfer between atoms.}$$ 23 / 45 Category: JAMB Chemistry 2023 23. $$\text{Alkane with straight-chain structure?}$$ a) $$\text{Cyclopentane.}$$ b) $$\text{Isobutane.}$$ c) $$\text{2-methyl propane.}$$ d) $$\text{Pentane.}$$ $$\text{Pentane has no branching, qualifying as straight chain.}$$ 24 / 45 Category: JAMB Chemistry 2023 24. $$\text{Products of NaCl electrolysis with inert electrodes?}$$ a) $$\text{H}_2\text{ at cathode, Cl}_2\text{ at anode.}$$ b) $$\text{H}_2\text{ at cathode, O}_2\text{ at anode.}$$ c) $$\text{Na metal, Cl}_2\text{ gas.}$$ d) $$\text{Na metal, O}_2\text{ gas.}$$ $$\text{H}_2\text{ at cathode, Cl}_2\text{ at anode from NaCl.}$$ 25 / 45 Category: JAMB Chemistry 2023 25. $$\text{Effect of diluting acidic solution on pH?}$$ a) $$\text{Depends on acid.}$$ b) $$\text{Decreases.}$$ c) $$\text{Remains same.}$$ d) $$\text{Increases.}$$ $$\text{Dilution reduces H}^+\text{ ion concentration, increasing pH.}$$ 26 / 45 Category: JAMB Chemistry 2023 26. $$\text{Factor NOT affecting reaction rate?}$$ a) $$\text{Reactant concentration.}$$ b) $$\text{Catalyst presence.}$$ c) $$\text{Product molecular weight.}$$ d) $$\text{Temperature.}$$ $$\text{Reaction rate doesn’t depend on product molecular weight.}$$ 27 / 45 Category: JAMB Chemistry 2023 27. $$\text{Organic compound responsible for fruit aroma?}$$ a) $$\text{Alkane.}$$ b) $$\text{Alkyne.}$$ c) $$\text{Ester.}$$ d) $$\text{Amine.}$$ $$\text{Esters impart distinct fruity scents.}$$ 28 / 45 Category: JAMB Chemistry 2023 28. $$\text{Molar mass of H}_2\text{O}?$$ a) $$\text{18 g/mol.}$$ b) $$\text{22 g/mol.}$$ c) $$\text{16 g/mol.}$$ d) $$\text{12 g/mol.}$$ $$\text{H}_2 = 2 + \text{O} = 16, \text{Total: } 18 \text{ g/mol.}$$ 29 / 45 Category: JAMB Chemistry 2023 29. $$\text{Chemical formula of rust?}$$ a) $$\text{Fe}_3\text{O}_4\text{.}$$ b) $$\text{FeO.}$$ c) $$\text{Fe(OH)}_3\text{.}$$ d) $$\text{Fe}_2\text{O}_3\text{.}$$ $$\text{Rust: Fe}_2\text{O}_3\cdot \text{H}_2\text{O forms with oxygen/moisture.}$$ 30 / 45 Category: JAMB Chemistry 2023 30. $$\text{Number of } \pi \text{ bonds in an alkene with 6 carbons?}$$ a) $$\text{4.}$$ b) $$\text{6.}$$ c) $$\text{5.}$$ d) $$\text{3.}$$ $$\text{One } \pi \text{ bond for each double bond in alkenes.}$$ 31 / 45 Category: JAMB Chemistry 2023 31. $$\text{Principal ore of iron?}$$ a) $$\text{Calcite.}$$ b) $$\text{Bauxite.}$$ c) $$\text{Magnetite.}$$ d) $$\text{Hematite.}$$ $$\text{Hematite is a major iron ore.}$$ 32 / 45 Category: JAMB Chemistry 2023 32. $$\text{Group of calcium in periodic table?}$$ a) $$\text{Alkaline earth metals.}$$ b) $$\text{Halogens.}$$ c) $$\text{Alkali metals.}$$ d) $$\text{Noble gases.}$$ $$\text{Calcium belongs to Alkaline Earth Metals.}$$ 33 / 45 Category: JAMB Chemistry 2023 33. $$\text{Primary constituent of crude oil?}$$ a) $$\text{Pentane.}$$ b) $$\text{Ethanol.}$$ c) $$\text{Heptane.}$$ d) $$\text{Methane.}$$ $$\text{Methane is a primary hydrocarbon in crude oil.}$$ 34 / 45 Category: JAMB Chemistry 2023 34. $$\text{Main source of carbon monoxide in urban areas?}$$ a) $$\text{Volcanic eruptions.}$$ b) $$\text{Vehicle emissions.}$$ c) $$\text{Forest fires.}$$ d) $$\text{Industrial processes.}$$ $$\text{Vehicle emissions release most CO in cities.}$$ 35 / 45 Category: JAMB Chemistry 2023 35. $$\text{Empirical formula of compound with 40% C, 6.67% H, and 53.33% O?}$$ a) $$\text{C}_4\text{H}_8\text{O}_4\text{.}$$ b) $$\text{CH}_2\text{O.}$$ c) $$\text{C}_2\text{H}_4\text{O}_2\text{.}$$ d) $$\text{C}_3\text{H}_6\text{O}_3\text{.}$$ $$\text{Simplify ratios to determine CH}_2\text{O empirical formula.}$$ 36 / 45 Category: JAMB Chemistry 2023 36. $$\text{True statement about acids?}$$ a) $$\text{All acids strong.}$$ b) $$\text{Bitter taste.}$$ c) $$\text{Turn litmus red.}$$ d) $$\text{pH > 7.}$$ $$\text{Acids turn blue litmus paper red.}$$ 37 / 45 Category: JAMB Chemistry 2023 37. $$\text{Bond formed by electron pair sharing?}$$ a) $$\text{Ionic.}$$ b) $$\text{Covalent.}$$ c) $$\text{Hydrogen.}$$ d) $$\text{Metallic.}$$ $$\text{Covalent bonds involve shared electron pairs.}$$ 38 / 45 Category: JAMB Chemistry 2023 38. $$\text{Effect of adding salt to boiling point of water?}$$ a) $$\text{Decreases.}$$ b) $$\text{Unchanged.}$$ c) $$\text{Increases.}$$ d) $$\text{Unpredictable.}$$ $$\text{Salt increases water boiling point (boiling point elevation).}$$ 39 / 45 Category: JAMB Chemistry 2023 39. $$\text{Process converting gas to liquid?}$$ a) $$\text{Condensation.}$$ b) $$\text{Evaporation.}$$ c) $$\text{Sublimation.}$$ d) $$\text{Freezing.}$$ $$\text{Condensation changes gas phase to liquid.}$$ 40 / 45 Category: JAMB Chemistry 2023 40. $$\text{Example of decomposition reaction?}$$ a) $$\text{2H}_2\text{ + O}_2\text{.}$$ b) $$\text{2H}_2\text{O to } 2H}_2\text{.}$$ c) $$\text{Na + Cl}_2\text{.}$$ d) $$\text{CaCO}_3\text{ to CaO + CO}_2\text{.}$$ $$\text{CaCO}_3 \rightarrow \text{CaO + CO}_2\text{ breaks one compound into simpler products.}$$ 41 / 45 Category: JAMB Chemistry 2023 41. $$\text{Reason for leaf color change during autumn?}$$ a) $$\text{Decreased chlorophyll.}$$ b) $$\text{Increased water uptake.}$$ c) $$\text{Increased light.}$$ d) $$\text{Decreased temperature.}$$ $$\text{Decreased chlorophyll production reveals other pigments.}$$ 42 / 45 Category: JAMB Chemistry 2023 42. $$\text{Function of sodium-potassium pump in cells?}$$ a) $$\text{Maintains gradient.}$$ b) $$\text{Synthesizes proteins.}$$ c) $$\text{Produces ATP.}$$ d) $$\text{Absorbs nutrients.}$$ $$\text{Maintains electrochemical gradient vital for cell function.}$$ 43 / 45 Category: JAMB Chemistry 2023 43. $$\text{Most electronegative element?}$$ a) $$\text{Sodium.}$$ b) $$\text{Calcium.}$$ c) $$\text{Fluorine.}$$ d) $$\text{Chlorine.}$$ $$\text{Fluorine has the highest electronegativity on periodic table.}$$ 44 / 45 Category: JAMB Chemistry 2023 44. $$\text{Main product of hydrocarbon combustion?}$$ a) $$\text{Carbon monoxide.}$$ b) $$\text{CO}_2\text{ and H}_2\text{O.}$$ c) $$\text{Carbon soot.}$$ d) $$\text{Hydrogen gas.}$$ $$\text{CO}_2 \text{ and H}_2\text{O are complete combustion products.}$$ 45 / 45 Category: JAMB Chemistry 2023 45. $$\text{Energy-releasing biological process?}$$ a) $$\text{Photosynthesis.}$$ b) $$\text{Respiration.}$$ c) $$\text{Melting.}$$ d) $$\text{Sublimation.}$$ $$\text{Respiration releases energy by metabolizing glucose.}$$ Your score is The average score is 0% LinkedIn Facebook Twitter 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