2018 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 2018 JAMB CHEMISTRY PAST QUESTIONS AND ANSWERS 1 / 40 Category: Jamb Chemistry 2018 1. $$\text{Periodic classification arranges elements based on what property?}$$ a) $$\text{Atomic weights.}$$ b) $$\text{Isotopic weights.}$$ c) $$\text{Molecular weights.}$$ d) $$\text{Atomic numbers.}$$ $$\text{Elements are arranged by atomic numbers, determining the periodic trends and chemical properties.}$$ 2 / 40 Category: Jamb Chemistry 2018 2. $$\text{What is the new concentration after diluting 1L of 2.2M H}_2\text{SO}_4?$$ a) $$\text{2.2 M.}$$ b) $$\text{1.1 M.}$$ c) $$\text{0.22 M.}$$ d) $$\text{0.11 M.}$$ $$\text{Use dilution formula } C_1V_1 = C_2V_2 \text{ to calculate resulting concentration after mixing in 10L of water.}$$ 3 / 40 Category: Jamb Chemistry 2018 3. $$\text{In the experiment, what happens to litmus paper initially?}$$ a) $$\text{Bleached.}$$ b) $$\text{Green.}$$ c) $$\text{Red.}$$ d) $$\text{Blue.}$$ $$\text{Litmus paper turns red in acidic environments. It indicates the presence of H}^+\text{ ions.}$$ 4 / 40 Category: Jamb Chemistry 2018 4. $$\text{How to correct the electrochemical series order of given elements?}$$ a) $$\text{Al and Mg.}$$ b) $$\text{Zn and Fe.}$$ c) $$\text{Zn and Pb.}$$ d) $$\text{Pb and H.}$$ $$\text{Switch positions of Zn and Fe for accurate arrangement based on standard electrode potentials.}$$ 5 / 40 Category: Jamb Chemistry 2018 5. $$\text{What kinetic theory assumption explains gas molecules’ straight-line motion?}$$ a) $$\text{Elastic collisions.}$$ b) $$\text{Repulsion forces.}$$ c) $$\text{Attraction-repulsion.}$$ d) $$\text{Inelastic collisions.}$$ $$\text{Molecules collide elastically, conserving energy during interactions.}$$ 6 / 40 Category: Jamb Chemistry 2018 6. $$\text{Factors affecting solubility of gases in solvents include?}$$ a) $$\text{All factors.}$$ b) $$\text{Solvent/solute.}$$ c) $$\text{Solute alone.}$$ d) $$\text{Solvent/temp/pressure.}$$ $$\text{Solubility depends on solvent/solute nature, temperature, and pressure.}$$ 7 / 40 Category: Jamb Chemistry 2018 7. $$\text{Identify correct periodic table trend description.}$$ a) $$\text{Same valence.}$$ b) $$\text{Increase valence.}$$ c) $$\text{Same shells.}$$ d) $$\text{Decreasing nonmetals.}$$ $$\text{Valence electrons increase progressively across a period, indicating chemical behavior changes.}$$ 8 / 40 Category: Jamb Chemistry 2018 8. $$\text{Boiling fat with caustic soda is referred to as?}$$ a) $$\text{Hydrolysis.}$$ b) $$\text{Esterification.}$$ c) $$\text{Acidification.}$$ d) $$\text{Saponification.}$$ $$\text{Saponification involves hydrolysis of fats into glycerol and soap in alkaline conditions.}$$ 9 / 40 Category: Jamb Chemistry 2018 9. $$\text{Which substances form higher oxides with oxygen?}$$ a) $$\text{CO}_2 \text{, H}_2\text{O.}$$ b) $$\text{NO, H}_2\text{O.}$$ c) $$\text{CO, CO}_2.}$$ d) $$\text{SO}_2 \text{, NO.}$$ $$\text{SO}_2 \text{ and NO undergo further oxidation, yielding higher oxidation states.}$$ 10 / 40 Category: Jamb Chemistry 2018 10. $$\text{Why does MnO}_2 \text{reduce energy need in KClO}_3 \text{ reaction?}$$ a) $$\text{Lower pressure.}$$ b) $$\text{Increase area.}$$ c) $$\text{Higher reaction rate.}$$ d) $$\text{Lower energy barrier.}$$ $$\text{Catalyst lowers activation energy, allowing reaction at moderate heat.}$$ 11 / 40 Category: Jamb Chemistry 2018 11. $$\text{How to obtain pure water from a mixture of sand, water, and methanoic acid?}$$ a) $$\text{Fractional distillation.}$$ b) $$\text{Filtration + distillation.}$$ c) $$\text{Neutralize + distillation.}$$ d) $$\text{Neutralize + filtration.}$$ $$\text{Filtration removes sand; distillation separates water due to different boiling points.}$$ 12 / 40 Category: Jamb Chemistry 2018 12. $$\text{Mass of aluminum liberated by same electricity as 3.6g of silver.}$$ a) $$\text{2.7 g.}$$ b) $$\text{1.2 g.}$$ c) $$\text{0.9 g.}$$ d) $$\text{0.3 g.}$$ $$\text{Using electrolysis proportionality: }\frac{\text{Mass of Al}}{\text{Mass of Ag}} = \frac{\text{Molar mass Al}}{\text{Molar mass Ag}}.}$$ 13 / 40 Category: Jamb Chemistry 2018 13. $$\text{What reagents are suitable for nitrogen preparation in a lab?}$$ a) $$\text{Sodium dioxonitrate (III), ammonium chloride.}$$ b) $$\text{Sodium trioxonitrate (V), ammonium chloride.}$$ c) $$\text{NaCl, ammonium nitrate.}$$ d) $$\text{NaCl, ammonium dioxonitrate (III).}$$ $$\text{Sodium dioxonitrate reacts with ammonium chloride to yield nitrogen gas.}$$ 14 / 40 Category: Jamb Chemistry 2018 14. $$\text{How many electrons are in the valence shell of an element with atomic number 14?}$$ a) $$\text{1.}$$ b) $$\text{2.}$$ c) $$\text{3.}$$ d) $$\text{4.}$$ $$\text{Atomic number 14 corresponds to silicon; configuration } 1s^2 2s^2 2p^6 3s^2 3p^2 \text{ gives 4 valence electrons.}$$ 15 / 40 Category: Jamb Chemistry 2018 15. $$\text{Volume of oxygen remaining after reacting 8cm}^3\text{ H}_2\text{ with 20cm}^3\text{ O}_2?$$ a) $$\text{10cm}^3.}$$ b) $$\text{12cm}^3.}$$ c) $$\text{14cm}^3.}$$ d) $$\text{16cm}^3.}$$ $$\text{Using stoichiometry: H}_2 + \frac{1}{2}O_2 \rightarrow H_2O; \text{ oxygen remaining = 12cm}^3.}$$ 16 / 40 Category: Jamb Chemistry 2018 16. $$\text{Which oxide is not reduced by hydrogen or carbon?}$$ a) $$\text{Lead oxide.}$$ b) $$\text{Magnesium oxide.}$$ c) $$\text{Copper oxide.}$$ d) $$\text{Tin oxide.}$$ $$\text{Magnesium oxide is highly stable and resistant to reduction at normal conditions.}$$ 17 / 40 Category: Jamb Chemistry 2018 17. $$\text{What is the correct name for this alkane compound?}$$ a) $$\text{1-methylpentane.}$$ b) $$\text{3-methylbutane.}$$ c) $$\text{2-methylbutane.}$$ d) $$\text{1-dimethylpropane.}$$ $$\text{IUPAC naming rules yield } 2\text{-methylbutane } \text{as the correct name for this isomer.}$$ 18 / 40 Category: Jamb Chemistry 2018 18. $$\text{Which cation forms a white precipitate soluble in both NaOH and NH}_3?$$ a) $$\text{Zn}^2+$$ b) $$\text{Ca}^2+$$ c) $$\text{Al}^3+$$ d) $$\text{Pb}^2+$$ $$\text{Zn}^2+ \text{ forms amphoteric compounds, dissolving in both bases and ammonia solutions.}$$ 19 / 40 Category: Jamb Chemistry 2018 19. $$\text{Calculate NaOH concentration for 2g dissolved in 100cm}^3\text{ solution.}$$ a) $$\text{0.40 mol dm}^3.}$$ b) $$\text{0.50 mol dm}^3.}$$ c) $$\text{0.05 mol dm}^3.}$$ d) $$\text{0.30 mol dm}^3.}$$ $$\text{Concentration } C = \frac{\text{Mass}}{\text{Molar mass} \times \text{Volume (L)}} \text{ yields 0.50 mol dm}^3.}$$ 20 / 40 Category: Jamb Chemistry 2018 20. $$\text{How many atoms are in 6.0g of magnesium?}$$ a) $$\text{1.20 x 10}^2\text{2.}$$ b) $$\text{2.41 x 10}^2\text{2.}$$ c) $$\text{1.51 x 10}^3\text{2.}$$ d) $$\text{3.02 x 10}^3\text{2.}$$ $$\text{Using formula } \text{Atoms = Moles } \times N_A; \text{ moles = } \frac{\text{Mass}}{\text{Molar mass}}.}$$ 21 / 40 Category: Jamb Chemistry 2018 21. $$\text{Which radioisotope is used for checking faults in welds and castings?}$$ a) $$\text{Carbon-14.}$$ b) $$\text{Phosphorus-32.}$$ c) $$\text{Cobalt-60.}$$ d) $$\text{Iodine-131.}$$ $$\text{Cobalt-60 emits gamma radiation, suitable for industrial imaging to check welds and castings.}$$ 22 / 40 Category: Jamb Chemistry 2018 22. $$\text{Why do beryllium and aluminum share similar properties?}$$ a) $$\text{Both are metals.}$$ b) $$\text{Same group.}$$ c) $$\text{Same period.}$$ d) $$\text{Diagonal relationship.}$$ $$\text{Diagonal relationships in the periodic table lead to similarities in chemical properties.}$$ 23 / 40 Category: Jamb Chemistry 2018 23. $$\text{What is the equilibrium constant for } mE + nF \rightleftharpoons pG + qH?$$ a) $$\frac{[E]^m[F]^n}{[G]^p[H]^q}$$ b) $$\frac{[E][F]}{[G][H]}$$ c) $$\frac{[G]^p[H]^q}{[E]^m[F]^n}$$ d) $$\frac{[G][H]}{[E][F]}$$ $$\text{Equilibrium constant } K = \frac{[G]^p[H]^q}{[E]^m[F]^n}.}$$ 24 / 40 Category: Jamb Chemistry 2018 24. $$\text{What do reactions of ammonia demonstrate? } \text{ (e.g. reducing CuO, forming HCl.)}$$ a) $$\text{Basic properties.}$$ b) $$\text{Acidic properties.}$$ c) $$\text{Reducing properties.}$$ d) $$\text{Oxidizing properties.}$$ $$\text{Ammonia acts as a reducing agent in these chemical reactions.}$$ 25 / 40 Category: Jamb Chemistry 2018 25. $$\text{What salt reacts with HCl to produce a gas that decolorizes acidified KMnO}_4?$$ a) $$\text{Na}_2\text{SO}_4.}$$ b) $$\text{Na}_2\text{SO}_3.}$$ c) $$\text{Na}_2\text{S.}$$ d) $$\text{Na}_2\text{CO}_3.}$$ $$\text{Sodium sulfite reacts to produce SO}_2 \text{ gas, decolorizing KMnO}_4\text{.}$$ 26 / 40 Category: Jamb Chemistry 2018 26. $$\text{What gives soda water and soft drinks their characteristic taste?}$$ a) $$\text{CO}_2\text{ (carbon IV oxide).}$$ b) $$\text{CO (carbon II oxide).}$$ c) $$\text{Soda.}$$ d) $$\text{Glucose.}$$ $$\text{The taste comes from dissolved CO}_2 \text{ forming carbonic acid.}$$ 27 / 40 Category: Jamb Chemistry 2018 27. $$\text{Which of the following are mixtures? Petroleum, rubber latex, vulcanizer solution, CS}_2?$$ a) $$\text{Petroleum, latex, vulcanizer solution.}$$ b) $$\text{Petroleum, latex, CS}_2.}$$ c) $$\text{Petroleum and latex only.}$$ d) $$\text{Petroleum and CS}_2.}$$ $$\text{Petroleum, latex, and vulcanizer’s solution are mixtures. Carbon disulfide is a compound.}$$ 28 / 40 Category: Jamb Chemistry 2018 28. $$\text{A balanced equation obeys which law? Conservation of mass, proportions, or energy?}$$ a) $$\text{Mass conservation.}$$ b) $$\text{Definite proportions.}$$ c) $$\text{Multiple proportions.}$$ d) $$\text{Energy conservation.}$$ $$\text{Balanced equations show the law of conservation of mass: matter is neither created nor destroyed.}$$ 29 / 40 Category: Jamb Chemistry 2018 29. $$\text{What are the moles of a gas occupying 10dm}^3 \text{ at 4 atm and 273°C?}$$ a) $$\text{0.89 mol.}$$ b) $$\text{1.90 mol.}$$ c) $$\text{3.80 mol.}$$ d) $$\text{5.70 mol.}$$ $$\text{Using PV = nRT, solving for } n \text{ gives } \frac{P \cdot V}{R \cdot T} \approx 0.89 \text{ moles.}$$ 30 / 40 Category: Jamb Chemistry 2018 30. $$\text{At what temperature does gas volume reach zero by Charles’ Law?}$$ a) $$\text{0°C.}$$ b) $$\text{-100°C.}$$ c) $$\text{-273°C.}$$ d) $$\text{-373°C.}$$ $$\text{Absolute zero is -273°C, where gas theoretically has zero volume.}$$ 31 / 40 Category: Jamb Chemistry 2018 31. $$\text{Which substance is used to ripen fruits?}$$ a) $$\text{Ethene.}$$ b) $$\text{Propane.}$$ c) $$\text{Methane.}$$ d) $$\text{Butane.}$$ $$\text{Ethene acts as a natural ripening agent for fruits.}$$ 32 / 40 Category: Jamb Chemistry 2018 32. $$\text{Which sulfide is insoluble in dilute HCl? FeS, CuS, ZnS, or Na}_2\text{S?}$$ a) $$\text{FeS.}$$ b) $$\text{CuS.}$$ c) $$\text{ZnS.}$$ d) $$\text{Na}_2\text{S.}$$ $$\text{CuS is insoluble in dilute hydrochloric acid due to its low solubility.}$$ 33 / 40 Category: Jamb Chemistry 2018 33. $$\text{What is the pH of a 0.001 moldm}^{-3} \text{ NaOH solution?}$$ a) $$\text{14.}$$ b) $$\text{13.}$$ c) $$\text{12.}$$ d) $$\text{11.}$$ $$\text{Using } pH = 14 – pOH \text{ and pOH } = -\log[OH^-], pH = 11.}$$ 34 / 40 Category: Jamb Chemistry 2018 34. $$\text{What type of bonding exists in [Cu(NH}_3]_4^{2+}?$$ a) $$\text{Coordinate.}$$ b) $$\text{Electrovalent.}$$ c) $$\text{Metallic.}$$ d) $$\text{Covalent.}$$ $$\text{Coordinate bonding exists between Cu}^{2+} \text{ and NH}_3 \text{ ligands.}$$ 35 / 40 Category: Jamb Chemistry 2018 35. $$\text{Which is an example of chemical change? Dissolution, rusting, melting, or distillation?}$$ a) $$\text{Dissolution.}$$ b) $$\text{Rusting.}$$ c) $$\text{Melting.}$$ d) $$\text{Distillation.}$$ $$\text{Rusting is a chemical change involving oxidation.}$$ 36 / 40 Category: Jamb Chemistry 2018 36. $$\text{To double gas volume and pressure, to what temperature must gas at 273K be heated?}$$ a) $$\text{298K.}$$ b) $$\text{546K.}$$ c) $$\text{819K.}$$ d) $$\text{1092K.}$$ $$\text{Applying ideal gas law, doubling both volume and pressure requires T = 1092K.}$$ 37 / 40 Category: Jamb Chemistry 2018 37. $$\text{What happens to particle kinetic energy with temperature rise?}$$ a) $$\text{Decreases.}$$ b) $$\text{Increases.}$$ c) $$\text{Becomes zero.}$$ d) $$\text{Remains constant.}$$ $$\text{Kinetic energy increases as particle motion becomes faster.}$$ 38 / 40 Category: Jamb Chemistry 2018 38. $$\text{Which element is used in match production?}$$ a) $$\text{Nitrogen.}$$ b) $$\text{Aluminum.}$$ c) $$\text{Copper.}$$ d) $$\text{Sulfur.}$$ $$\text{Sulfur is a key component in match production for ignition.}$$ 39 / 40 Category: Jamb Chemistry 2018 39. $$\text{Which gas cannot be dried using concentrated H}_2\text{SO}_4? HCl, NH}_3\text{, Cl}_2\text{, SO}_2?$$ a) $$\text{HCl.}$$ b) $$\text{NH}_3\text{.}$$ c) $$\text{Cl}_2\text{.}$$ d) $$\text{SO}_2\text{.}$$ $$\text{Ammonia reacts with concentrated sulfuric acid, so it cannot be dried using it.}$$ 40 / 40 Category: Jamb Chemistry 2018 40. $$\text{Consecutive alkanes differ by what unit? CH, CH}_2\text{, CH}_3\text{, C}_n\text{H}_n\text{?}$$ a) $$\text{CH.}$$ b) $$\text{CH}_2\text{.}$$ c) $$\text{CH}_3\text{.}$$ d) $$\text{C}_n\text{H}_n.}$$ $$\text{Consecutive members of an alkane homologous series differ by CH}_2 \text{ group.}$$ Your score is The average score is 0% LinkedIn Facebook Twitter VKontakte 0% Restart quiz Anonymous feedback Send feedback
