2017 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 2017 JAMB CHEMISTRY PAST QUESTIONS AND ANSWERS 1 / 45 Category: Jamb Chemistry 2017 1. $$\text{What flame is used by welders for cutting metals?}$$ a) $$\text{Butane gas flame.}$$ b) $$\text{Acetylene flame.}$$ c) $$\text{Kerosene flame.}$$ d) $$\text{Oxy-acetylene flame.}$$ $$\text{The oxy-acetylene flame burns at a high temperature, making it suitable for welding and cutting metals.}$$ 2 / 45 Category: Jamb Chemistry 2017 2. $$\text{At room temperature, solubility comparison in Fig. 1 shows?}$$ a) $$\text{Y is twice as soluble as X.}$$ b) $$\text{X is twice as soluble as Y.}$$ c) $$\text{X and Y are equally soluble.}$$ d) $$\text{X is three times as soluble as Y.}$$ $$\text{Y is observed to be twice as soluble as X in the provided solubility data.}$$ 3 / 45 Category: Jamb Chemistry 2017 3. $$\text{Calculate enthalpy change for SO}_3(g)\text{ + H}_2O(l) \to H}_2\text{SO}_4(l).$$ a) $$\text{-1032 KJ.}$$ b) $$\text{-130 KJ.}$$ c) $$\text{+130 KJ.}$$ d) $$\text{+1032 KJ.}$$ $$\text{Using enthalpy of formation values, ΔH = ΣH(products) – ΣH(reactants). ΔH = (-811) – [(-395) + (-286)].}$$ 4 / 45 Category: Jamb Chemistry 2017 4. $$\text{What law is demonstrated by the data for Y and Z?}$$ a) $$\text{Multiple proportions.}$$ b) $$\text{Conservation of mass.}$$ c) $$\text{Constant composition.}$$ d) $$\text{Reciprocal proportion.}$$ $$\text{The data showing multiple ratios of elements between Y and Z corresponds to the law of multiple proportions.}$$ 5 / 45 Category: Jamb Chemistry 2017 5. $$\text{Identify the correct nuclear equation when neutrons bombard an element.}$$ a) $$\text{y}_z\text{X + n}^0 \to y-1_{z+1}\text{X.}$$ b) $$\text{y}_z\text{X + n}^0 \to y+1_{z}\text{X.}$$ c) $$\text{y}_z\text{X + n}^0 \to y_{z+1}\text{X.}$$ d) $$\text{y}_z\text{X + n}^0 \to y+1_{z+1}\text{X.}$$ $$\text{The correct equation shows an increase in mass number (neutron addition) without altering the atomic number.}$$ 6 / 45 Category: Jamb Chemistry 2017 6. $$\text{Vapour density of a gas is defined as?}$$ a) $$\text{Mass vs. water vapour.}$$ b) $$\text{Mass vs. hydrogen.}$$ c) $$\text{Mass vs. oxygen.}$$ d) $$\text{Mass minus vapour pressure.}$$ $$\text{Vapour density compares the mass of a gas to hydrogen under the same conditions.}$$ 7 / 45 Category: Jamb Chemistry 2017 7. $$\text{What is the new pressure if oxygen expands to 20dm}^3\text{ from 30cm}^3 \text{ at 10 atm?}$$ a) $$\text{6.7 atm.}$$ b) $$\text{15.0 atm.}$$ c) $$\text{60.0 atm.}$$ d) $$\text{66.0 atm.}$$ $$\text{Using Boyle’s Law, P1V1 = P2V2, the pressure is recalculated for the expanded volume.}$$ 8 / 45 Category: Jamb Chemistry 2017 8. $$\text{When does a liquid boil?}$$ a) $$\text{Vapour pressure matches solid.}$$ b) $$\text{Molecules escape surface.}$$ c) $$\text{Vapour equals atmospheric pressure.}$$ d) $$\text{Volume slightly increases.}$$ $$\text{Boiling occurs when vapour pressure of a liquid equals atmospheric pressure, enabling free vaporization.}$$ 9 / 45 Category: Jamb Chemistry 2017 9. $$\text{Which element among W, X, Y, Z is a metal (atomic numbers 2, 6, 16, 20)?}$$ a) $$\text{X.}$$ b) $$\text{W.}$$ c) $$\text{Z.}$$ d) $$\text{Y.}$$ $$\text{Element Z (atomic number 20) is calcium, a Group II metal.}$$ 10 / 45 Category: Jamb Chemistry 2017 10. $$\text{What happens to an electrometer struck by cathode rays?}$$ a) $$\text{Negatively charged.}$$ b) $$\text{Positively charged.}$$ c) $$\text{Neutral.}$$ d) $$\text{Bipolar.}$$ $$\text{Cathode rays consist of electrons, imparting a negative charge upon contact with the electrometer.}$$ 11 / 45 Category: Jamb Chemistry 2017 11. $$\text{What process involves heating hydrocarbons to form smaller molecules?}$$ a) $$\text{Disintegration.}$$ b) $$\text{Polymerization.}$$ c) $$\text{Cracking.}$$ d) $$\text{Degradation.}$$ $$\text{Cracking breaks large hydrocarbon molecules into smaller ones, often for fuel production.}$$ 12 / 45 Category: Jamb Chemistry 2017 12. $$\text{In reaction of sulphuric acid with sugar, it acts as?}$$ a) $$\text{Drying agent.}$$ b) $$\text{Oxidizing agent.}$$ c) $$\text{Dehydrating agent.}$$ d) $$\text{Reducing agent.}$$ $$\text{The sulphuric acid removes water from sugar, acting as a dehydrating agent.}$$ 13 / 45 Category: Jamb Chemistry 2017 13. $$\text{What is the composition of smoke?}$$ a) $$\text{Solid in liquid.}$$ b) $$\text{Solid in gas.}$$ c) $$\text{Gas in liquid.}$$ d) $$\text{Liquid in liquid.}$$ $$\text{Smoke consists of solid or liquid particles dispersed in a gas medium.}$$ 14 / 45 Category: Jamb Chemistry 2017 14. $$\text{Electrolysis of dilute H}_2\text{SO}_4\text{: products at cathode and anode?}$$ a) $$\text{Sulphur, Hydrogen.}$$ b) $$\text{Hydrogen, Oxygen.}$$ c) $$\text{Oxygen, Hydrogen.}$$ d) $$\text{Hydrogen, Sulphate.}$$ $$\text{At the cathode, hydrogen is released; oxygen is released at the anode during electrolysis of H}_2\text{SO}_4.}$$ 15 / 45 Category: Jamb Chemistry 2017 15. $$\text{How to increase yield of R in reaction P(g) + Q(g) ⇋ 3R(s) + S(g)?}$$ a) $$\text{Larger vessel.}$$ b) $$\text{Higher temperature.}$$ c) $$\text{Remove some S.}$$ d) $$\text{Positive catalyst.}$$ $$\text{Removing S shifts equilibrium to favor product formation (Le Chatelier’s Principle).}$$ 16 / 45 Category: Jamb Chemistry 2017 16. $$\text{What is the mass of silver deposited with 10A in 4830s?}$$ a) $$\text{108.0g.}$$ b) $$\text{54.0g.}$$ c) $$\text{27.0g.}$$ d) $$\text{13.5g.}$$ $$\text{Using Q = It and molar mass of silver, calculate mass from moles of electrons deposited.}$$ 17 / 45 Category: Jamb Chemistry 2017 17. $$\text{Calculate ΔH for CO(g) + H}_2\text{O(g)} → \text{CO}_2\text{(g) + H}_2\text{(g)}.}$$ a) $$\text{-282 KJ/mol.}$$ b) $$\text{-42 KJ/mol.}$$ c) $$\text{+42 KJ/mol.}$$ d) $$\text{+262 KJ/mol.}$$ $$\text{Use ΔH = ΣH(products) – ΣH(reactants). Data provided: CO2 = -394 KJ, H2O = -242 KJ, CO = -110 KJ.}$$ 18 / 45 Category: Jamb Chemistry 2017 18. $$\text{How many unpaired electrons in 1s}^2 2s^2 2p^5?$$ a) $$\text{2.}$$ b) $$\text{5.}$$ c) $$\text{1.}$$ d) $$\text{4.}$$ $$\text{Fluorine’s electron configuration has 5 electrons in p-orbital, with 1 unpaired.}$$ 19 / 45 Category: Jamb Chemistry 2017 19. $$\text{Which gases demonstrate the fountain experiment?}$$ a) $$\text{(ii) and (iii).}$$ b) $$\text{(i) and (iii).}$$ c) $$\text{(ii) and (iv).}$$ d) $$\text{(ii) only.}$$ $$\text{Ammonia and hydrogen chloride react in the fountain experiment due to solubility and pressure changes.}$$ 20 / 45 Category: Jamb Chemistry 2017 20. $$\text{Why are transition metals colored?}$$ a) $$\text{f-orbital.}$$ b) $$\text{s-orbital.}$$ c) $$\text{p-orbital.}$$ d) $$\text{d-orbital.}$$ $$\text{Color results from d-orbital electron transitions absorbing specific light wavelengths.}$$ 21 / 45 Category: Jamb Chemistry 2017 21. $$\text{Which separation process yields } \geq 95\% \text{ ethanol from palm wine?}$$ a) $$\text{Without dehydrant.}$$ b) $$\text{Simple distillation.}$$ c) $$\text{Fractional distillation.}$$ d) $$\text{Column chromatography.}$$ $$\text{Fractional distillation with a dehydrant efficiently separates ethanol due to its volatility.}$$ 22 / 45 Category: Jamb Chemistry 2017 22. $$\text{Products from hydrolysis of esters?}$$ a) $$\text{Ether and acid.}$$ b) $$\text{Alcohol and acid.}$$ c) $$\text{Ketone and water.}$$ d) $$\text{Alcohol and water.}$$ $$\text{Esters hydrolyze into an alcohol and a carboxylic acid, breaking ester bonds.}$$ 23 / 45 Category: Jamb Chemistry 2017 23. $$\text{Electrons transferred in } 3\text{CuO + 2NH}_3$$ a) $$\text{4.0 x 10}^-23.}$$ b) $$\text{3.0 x 10}^-23.}$$ c) $$\text{1.2 x 10}^24.}$$ d) $$\text{6.0 x 10}^24.}$$ $$\text{Each mole of copper involves electron transfer calculated from stoichiometric coefficients.}$$ 24 / 45 Category: Jamb Chemistry 2017 24. $$\text{Unpaired electrons in } 1s^2 2s^2 2p^6 3s^2 3p^3?$$ a) $$\text{5.}$$ b) $$\text{4.}$$ c) $$\text{3.}$$ d) $$\text{2.}$$ $$\text{Element configuration reveals 3 unpaired electrons in its p-orbital.}$$ 25 / 45 Category: Jamb Chemistry 2017 25. $$\text{Correct reaction for X + CuSO}_4$$ a) $$\text{X(s) + CuSO}_4\text{(aq).}$$ b) $$\text{2X(s) + CuSO}_4\text{(aq).}$$ c) $$\text{XSO}_4\text{(aq).}$$ d) $$\text{3Cu(s).}$$ $$\text{Equation balancing shows correct stoichiometry between X and CuSO}_4\text{ reacting.}$$ 26 / 45 Category: Jamb Chemistry 2017 26. $$\text{Why use coke in blast furnace?}$$ a) $$\text{Reduce steel.}$$ b) $$\text{Earth impurities.}$$ c) $$\text{Steel formation.}$$ d) $$\text{Calcium carbonate decomposes.}$$ $$\text{Coke reduces iron oxides to iron and reacts with limestone to remove impurities.}$$ 27 / 45 Category: Jamb Chemistry 2017 27. $$\text{Bond between atoms Y and Z?}$$ a) $$\text{Ionic bond.}$$ b) $$\text{Covalent bond.}$$ c) $$\text{Dative bond.}$$ d) $$\text{Metallic bond.}$$ $$\text{Electron sharing forms covalent bonds between non-metals.}$$ 28 / 45 Category: Jamb Chemistry 2017 28. $$\text{Gas expands: final-to-initial temperature ratio?}$$ a) $$\text{3:1.}$$ b) $$\text{5:2.}$$ c) $$\text{5:4.}$$ d) $$\text{8:3.}$$ $$\text{Using ideal gas law, temperature ratio equals volume ratio at constant pressure.}$$ 29 / 45 Category: Jamb Chemistry 2017 29. $$\text{Chemical for coagulation in water purification?}$$ a) $$\text{Aluminium sulfate.}$$ b) $$\text{Copper sulfate.}$$ c) $$\text{Sodium sulfate.}$$ d) $$\text{Calcium sulfate.}$$ $$\text{Aluminium tetraoxosulphate(VI) facilitates coagulation by clumping impurities.}$$ 30 / 45 Category: Jamb Chemistry 2017 30. $$\text{What dissolves fats?}$$ a) $$\text{HCl acid.}$$ b) $$\text{Calcium hydroxide.}$$ c) $$\text{Kerosene.}$$ d) $$\text{Water.}$$ $$\text{Kerosene dissolves non-polar fats due to similar molecular structures.}$$ 31 / 45 Category: Jamb Chemistry 2017 31. $$\text{What gases remain after alkaline pyrogallol absorption?}$$ a) $$\text{Nitrogen and CO}_2.}$$ b) $$\text{Rare gases.}$$ c) $$\text{Nitrogen and oxygen.}$$ d) $$\text{Nitrogen and rare gases.}$$ $$\text{Alkaline pyrogallol absorbs oxygen; remaining gases are nitrogen and rare gases.}$$ 32 / 45 Category: Jamb Chemistry 2017 32. $$\text{Number of atoms in one mole of a substance equals?}$$ a) $$\text{Atomic number.}$$ b) $$\text{Avogadro number.}$$ c) $$\text{Gas constant.}$$ d) $$\text{Number of electrons.}$$ $$\text{Avogadro’s number defines the number of atoms or molecules in one mole.}$$ 33 / 45 Category: Jamb Chemistry 2017 33. $$\text{What indicates number of bonds atom forms?}$$ a) $$\text{Oxidation number.}$$ b) $$\text{Valence.}$$ c) $$\text{Atomic number.}$$ d) $$\text{Electronegativity.}$$ $$\text{Valence reflects the number of electrons available for bonding in an atom.}$$ 34 / 45 Category: Jamb Chemistry 2017 34. $$\text{What is the structural formula of ethanoic acid?}$$ a) $$\text{CH}_4.}$$ b) $$\text{CH}_3\text{OH.}$$ c) $$\text{CH}_3\text{CO.}$$ d) $$\text{CH}_3\text{COOH.}$$ $$\text{Ethanoic acid (acetic acid) has the formula CH}_3\text{COOH, containing carboxylic (-COOH) group.}$$ 35 / 45 Category: Jamb Chemistry 2017 35. $$\text{What worsens pollution from car exhaust?}$$ a) $$\text{Water vapor.}$$ b) $$\text{Steam.}$$ c) $$\text{Smoke.}$$ d) $$\text{Heavy metals.}$$ $$\text{Exhaust releases heavy metals like lead and hydrocarbons causing severe environmental effects.}$$ 36 / 45 Category: Jamb Chemistry 2017 36. $$\text{Volume of 0.5M H}_2\text{SO}_4 \text{neutralizing 20cm}^3\text{ of NaOH?}$$ a) $$\text{2.0 cm}^3.}$$ b) $$\text{5.0 cm}^3.}$$ c) $$\text{6.8 cm}^3.}$$ d) $$\text{8.3 cm}^3.}$$ $$\text{Using } M_1V_1 = M_2V_2, \text{ solve for H}_2\text{SO}_4 \text{ volume at 0.5M to neutralize.}$$ 37 / 45 Category: Jamb Chemistry 2017 37. $$\text{Which substance is an electrolyte?}$$ a) $$\text{Sodium acetate.}$$ b) $$\text{Solid KOH.}$$ c) $$\text{Mercury.}$$ d) $$\text{Alcohol.}$$ $$\text{Sodium acetate in solution conducts electricity, qualifying as an electrolyte.}$$ 38 / 45 Category: Jamb Chemistry 2017 38. $$\text{Reaction to increase rate: } \text{Na}_2\text{S}_2\text{O}_3 \text{+ HCl?}$$ a) $$\text{Low temp, low conc.}$$ b) $$\text{Low volume, high P.}$$ c) $$\text{Low temp, high conc.}$$ d) $$\text{High temp, high conc.}$$ $$\text{Higher temperature and concentration accelerate this reaction’s rate due to increased molecular collisions.}$$ 39 / 45 Category: Jamb Chemistry 2017 39. $$\text{Which substance has the lowest vapor density?}$$ a) $$\text{Ethanoic acid.}$$ b) $$\text{Propanol.}$$ c) $$\text{Dichloromethane.}$$ d) $$\text{Ethanal.}$$ $$\text{Ethanal has the lowest molar mass among choices, leading to lowest vapor density.}$$ 40 / 45 Category: Jamb Chemistry 2017 40. $$\text{How does impurity affect melting point?}$$ a) $$\text{Stable.}$$ b) $$\text{Reduced.}$$ c) $$\text{Increased.}$$ d) $$\text{Zero.}$$ $$\text{Impurities disrupt lattice structures, reducing melting points in crystalline solids.}$$ 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 VKontakte 0% Restart quiz Anonymous feedback Send feedback
