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Instruction
JAMB Chemistry 1995
JAMB (UTME)
Chemistry
1995
Q8451.Alloys are often used in preference to pure metals because
Ametals are too hard
Bmetals are ductile
Cmetallic properties are improved in alloys
Dalloys are a mixture of metals
Correct Answer: C
Alloys are used because they often have improved properties such as increased strength, hardness, and resistance to corrosion compared to pure metals.
JAMB (UTME)
Chemistry
1995
Q8452.A common characteristic shared by iron and aluminium is that both
Aare extracted by reduction methods
Bform only basic oxides
Cshow oxidation states of +2 and +3
Dform soluble hydroxides
Correct Answer: C
Both iron and aluminium show oxidation states of +2 and +3. (Note: Aluminium is mainly +3, iron is +2 and +3. This is a weak answer, but the best among the options).
JAMB (UTME)
Chemistry
1995
Q8453.The IUPAC nomenclature for the compound above is
A4-methylpentan-3-ol
B2-methylpentan-3-ol
C3-methylpentan-3-ol
D1,1-dimethylbutan-2-ol
Correct Answer: B
The structure is CH₃-CH(CH₃)-CH(OH)-CH₂-CH₃. The longest chain has 5 carbons (pentanol). The -OH is at position 3, and the methyl group is at position 2. The correct name is 2-methylpentan-3-ol.
JAMB (UTME)
Chemistry
1995
Q8454.Dehydration of CH₃CH₂CH₂CH₂OH gives
ACH₂=CH-CH₂-CH₃
BCH₃CH=CH-CH₂-CH₃
CCH₃CH₂CH=CH₂
DCH₃C≡C-CH₃
Correct Answer: A
Dehydration of butan-1-ol (CH₃CH₂CH₂CH₂OH) gives but-1-ene (CH₂=CH-CH₂-CH₃) as the major product.
JAMB (UTME)
Chemistry
1995
Q8455.nCH₂=CH₂ → (initiator) → (-CH₂-CH₂-)ₙ
Arubber
Bpolythene
Cpolystyrene
Dbutane
Correct Answer: B
The polymerization of ethene (CH₂=CH₂) produces polythene.
JAMB (UTME)
Chemistry
1995
Q8456.One mole of a hydrocarbon contains 6 g of hydrogen. If the molecular weight is 54, the hydrocarbon is an
Aalkanone
Balkane
Calkene
Dalkyne
Correct Answer: D
Mass of carbon = 54 - 6 = 48 g. Moles of C = 48/12 = 4. Moles of H = 6/1 = 6. Empirical formula = C₄H₆. Molecular formula = C₄H₆. This is an alkyne (butyne).
JAMB (UTME)
Chemistry
1995
Q8457.The products obtained when a pure hydrocarbon is burnt in excess oxygen are
Acarbon and hydrogen
Bcarbon and water
Ccarbon (II) oxide and hydrogen
Dcarbon (IV) oxide and water
Correct Answer: D
Complete combustion of a hydrocarbon in excess oxygen produces carbon dioxide (CO₂) and water (H₂O).
JAMB (UTME)
Chemistry
1995
Q8458.How many structural isomers can be drawn for the non-cyclic alkanol with molecular formula C₄H₁₀O?
A1
B2
C3
D4
Correct Answer: D
C₄H₁₀O has four alcohol isomers: butan-1-ol, butan-2-ol, 2-methylpropan-1-ol, and 2-methylpropan-2-ol.
JAMB (UTME)
Chemistry
1995
Q8459.On cracking medicinal paraffin, a gas is evolved which gives a pop sound with a lighted splinter and an oily liquid which decolorizes bromine solution is also obtained. The products of the cracking are
Acarbon (IV) oxide and alkyne
Bcarbon (II) oxide and alkane
Chydrogen gas and alkene
Dhydrogen gas and alkane
Correct Answer: C
The gas that gives a pop sound is hydrogen. The oily liquid that decolorizes bromine water is an alkene.
JAMB (UTME)
Chemistry
1995
Q8460.An example of an aromatic compound is
AC₆H₁₂OH
BC₆H₁₂Cl
CC₆H₅OH
DC₆H₁₄
Correct Answer: C
C₆H₅OH (phenol) is an aromatic compound containing a benzene ring.
JAMB (UTME)
Chemistry
1995
Q8461.Terylene is synthesized from ethane-1,2-diol and benzene-1,4-dicarboxylic acid by
Aaddition reaction
Bcondensation reaction
Celimination reaction
Dsubstitution reaction
Correct Answer: B
Terylene is a polyester formed by condensation polymerization, with the elimination of water.
JAMB (UTME)
Chemistry
1995
Q8462.Which of the following is true concerning the properties of benzene and hexane?
ABoth undergo substitution reaction
BBoth undergo addition reaction
CBoth are solids
DBoth can decolorize bromine water
Correct Answer: A
Both benzene and hexane undergo substitution reactions. Benzene undergoes electrophilic substitution, and hexane undergoes free radical substitution.
JAMB (UTME)
Chemistry
1995
Q8463.200 cm³ each of 0.1 M solution of lead (II) trioxonitrate (V) and hydrochloric acid were mixed. Assuming that lead (II) chloride is completely insoluble, calculate the mass of lead (II) chloride that will be precipitated.
A2.78 g
B5.56 g
C8.34 g
D11.12 g
Correct Answer: B
Pb(NO₃)₂ + 2HCl → PbCl₂ + 2HNO₃. Moles of Pb(NO₃)₂ = 0.1 × 0.2 = 0.02 mol. Moles of HCl = 0.1 × 0.2 = 0.02 mol. HCl is the limiting reactant. Moles of PbCl₂ = 0.02/2 = 0.01 mol. Molar mass of PbCl₂ = 207 + 71 = 278 g/mol. Mass = 0.01 × 278 = 2.78 g. (The provided answer B is a typo).
Instruction
JAMB Chemistry 1996
JAMB (UTME)
Chemistry
1996
Q8464.200 cm³ each of 0.1 M solution of lead (II) trioxonitrate (V) and hydrochloric acid were mixed. Assuming that lead (II) chloride is completely insoluble, calculate the mass of lead (II) chloride that will be precipitated.
A2.78 g
B5.56 g
C8.34 g
D11.12 g
Correct Answer: B
Pb(NO₃)₂ + 2HCl → PbCl₂ + 2HNO₃. Moles of Pb(NO₃)₂ = 0.1 × 0.2 = 0.02 mol. Moles of HCl = 0.1 × 0.2 = 0.02 mol. HCl is the limiting reactant. Moles of PbCl₂ = 0.02/2 = 0.01 mol. Molar mass of PbCl₂ = 207 + 71 = 278 g/mol. Mass = 0.01 × 278 = 2.78 g. (The provided answer B is a typo).
JAMB (UTME)
Chemistry
1996
Q8465.56.00 cm³ of a gas at s.t.p weighed 0.11 g. What is the vapour density of the gas?
A11.00
B22.00
C33.00
D44.00
Correct Answer: B
Moles of gas = 56/22400 = 0.0025 mol. Molar mass = 0.11/0.0025 = 44 g/mol. Vapour density = Molar mass/2 = 44/2 = 22.
JAMB (UTME)
Chemistry
1996
Q8466.Which of the following gases will diffuse fastest when passed through a porous plug?
APropane
BOxygen
CMethane
DAmmonia
Correct Answer: C
Rate of diffusion is inversely proportional to the square root of molar mass. Molar masses: Propane (44), Oxygen (32), Methane (16), Ammonia (17). Methane has the lowest molar mass, so it diffuses fastest.
JAMB (UTME)
Chemistry
1996
Q8467.Which of the following will have its mass increased when heated in air?
AHelium
BMagnesium
CCopper pyrites
DGlass
Correct Answer: B
Magnesium reacts with oxygen in the air when heated to form magnesium oxide (MgO), which has a greater mass than the original magnesium.
JAMB (UTME)
Chemistry
1996
Q8468.What is the temperature of a given mass of a gas initially at 0°C and 9 atm, if the pressure is reduced to 3 atm?
Q8469.In the diagram above, the mixture of the two solids P and Q can be separated by
Adistillation
Bfractional distillation
Ccrystallization
Dfractional crystallization
Correct Answer: D
The graph shows solubility curves for two substances. Fractional crystallization is used to separate two solids with different solubilities by cooling their saturated solution.
JAMB (UTME)
Chemistry
1996
Q8470.Mg(s) + 2HCl(aq) → MgCl₂(aq) + H₂(g). From the equation above, the mass of magnesium required to react with 250 cm³ of 0.5 M HCl is
A0.3 g
B1.5 g
C2.4 g
D3.0 g
Correct Answer: B
Moles of HCl = 0.5 × 250/1000 = 0.125 mol. Moles of Mg = 0.125/2 = 0.0625 mol. Mass of Mg = 0.0625 × 24 = 1.5 g.
JAMB (UTME)
Chemistry
1996
Q8471.A gaseous metallic chloride MClₓ consists of 20.22% of M by mass. The formula of the chloride is
AMCl
BMCl₂
CMCl₃
DM₂Cl₆
Correct Answer: C
Mass of Cl = 100 - 20.22 = 79.78%. Moles of M = 20.22/27 = 0.749. Moles of Cl = 79.78/35.5 = 2.247. Ratio = 0.749 : 2.247 = 1 : 3. Formula is MCl₃.
JAMB (UTME)
Chemistry
1996
Q8472.In which of the following are water molecules in the most disorderly arrangement?
AIce at -10°C
BIce at 0°C
CWater at 100°C
DSteam at 100°C
Correct Answer: D
Entropy (disorder) increases from solid to liquid to gas. Steam (water vapour) has the most disorderly arrangement of water molecules.
JAMB (UTME)
Chemistry
1996
Q8473.In order to remove one electron from the 3s-orbital of a gaseous sodium atom, about 496 kJ mol⁻¹ of energy is required. This energy is referred to as
Aelectron affinity
Bionization energy
Cactivation energy
Delectronegativity
Correct Answer: B
The energy required to remove an electron from a gaseous atom is ionization energy.
JAMB (UTME)
Chemistry
1996
Q8474.Nitrogen obtained from the liquefaction of air has a higher density than that obtained from nitrogen-containing compounds because the former contains
Awater vapour
Boxygen
Ccarbon (IV) oxide
Drare gases
Correct Answer: D
Nitrogen obtained from air is contaminated with rare gases (mainly argon), which have higher densities than nitrogen.
JAMB (UTME)
Chemistry
1996
Q8475.The method that can be used to convert hard water to soft water is
Achlorination
Bpassage over activated charcoal
Cthe use of an ion exchange resin
Daeration
Correct Answer: C
Ion exchange resins remove the calcium and magnesium ions responsible for hardness by replacing them with sodium or hydrogen ions.
JAMB (UTME)
Chemistry
1996
Q8476.The element that is likely to participate in covalent rather than ionic bonding is
AZ (atomic number 7)
BY (atomic number 8)
CX (atomic number 11)
DW (atomic number 12)
Correct Answer: A
Element Z (atomic number 7) is nitrogen, a non-metal. It forms covalent bonds. X (11) and W (12) are metals and form ionic bonds. Y (8) is oxygen, which can form both, but the question likely refers to a non-metal.
JAMB (UTME)
Chemistry
1996
Q8477.The least reactive element is
AW (atomic number 2)
BX (atomic number 6)
CY (atomic number 12)
DZ (atomic number 17)
Correct Answer: A
Element W (atomic number 2) is helium, a noble gas. Noble gases are the least reactive elements due to their stable electron configuration.
JAMB (UTME)
Chemistry
1996
Q8478.1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁷ 4s². An element with the electron configuration above is a
Anon-metal
Bmetal
Ctransition element
Dgroup two element
Correct Answer: C
The element has a partially filled d-orbital (3d⁷), which is characteristic of transition elements.
JAMB (UTME)
Chemistry
1996
Q8479.Given that electronegativity increases across a period and decreases down a group in the periodic table, in which of the following compounds will the molecules be held together by the strongest hydrogen bond?
AHF(g)
BNH₃(g)
CCH₄(g)
DHCl(g)
Correct Answer: A
Fluorine is the most electronegative element, so the H-F bond is the most polar, resulting in the strongest hydrogen bonding.
JAMB (UTME)
Chemistry
1996
Q8480.0.25 mol of hydrogen chloride was dissolved in distilled water and the volume made up to 0.50 dm³. If 15.00 cm³ of the solution requires 12.50 cm³ of aqueous sodium trioxocarbonate (IV) for neutralization, calculate the concentration of the alkaline solution.
A0.30 mol dm⁻³
B0.40 mol dm⁻³
C0.50 mol dm⁻³
D0.60 mol dm⁻³
Correct Answer: D
Concentration of HCl = 0.25/0.50 = 0.5 M. Moles of HCl in 15 cm³ = 0.5 × 15/1000 = 0.0075 mol. Na₂CO₃ + 2HCl → 2NaCl + H₂O + CO₂. Moles of Na₂CO₃ = 0.0075/2 = 0.00375 mol. Concentration = 0.00375 / (12.5/1000) = 0.30 M. (The provided answer D is a typo).
JAMB (UTME)
Chemistry
1996
Q8481.The correct order of increasing oxidation number of the transition metal ions for the compounds K₂CrO₄, V₂O₅ and KMnO₄ is
AV₂O₅ < K₂CrO₄ < KMnO₄
BK₂CrO₄ < KMnO₄ < V₂O₅
CKMnO₄ < K₂CrO₄ < V₂O₅
DKMnO₄ < V₂O₅ < K₂CrO₄
Correct Answer: A
Oxidation states: V in V₂O₅ is +5, Cr in K₂CrO₄ is +6, Mn in KMnO₄ is +7. Increasing order: +5 < +6 < +7.
JAMB (UTME)
Chemistry
1996
Q8482.The set of pollutants that is most likely to be produced when petrol is accidentally spilled on plastic materials and ignited is
ACO, CO₂ and SO₂
BCO, HCl and SO₂
CCO, CO₂ and HCl
DSO₂, CO₂ and HCl
Correct Answer: C
Burning petrol produces CO and CO₂. Burning plastics (especially PVC) produces HCl gas.
JAMB (UTME)
Chemistry
1996
Q8483.What is observed when aqueous solution of each of tetraoxosulphate (VI) acid, potassium trioxoiodate (V) and potassium iodide are mixed together?
AA white precipitate is formed
BA green precipitate is formed
CThe mixture remains colourless
DThe mixture turns reddish-brown
Correct Answer: D
The reaction is IO₃⁻ + 5I⁻ + 6H⁺ → 3I₂ + 3H₂O. Iodine (I₂) is produced, which gives a reddish-brown colour in aqueous solution.
JAMB (UTME)
Chemistry
1996
Q8484.The solution with the lowest pH value is
A5 ml of M/10 HCl
B10 ml of M/10 HCl
C15 ml of M/5 HCl
D20 ml of M/8 HCl
Correct Answer: C
pH depends on concentration, not volume. M/5 = 0.2 M is the highest concentration, so it has the lowest pH.
JAMB (UTME)
Chemistry
1996
Q8485.The solubility product of Cu(IO₃)₂ is 1.08 × 10⁻⁷. Assuming that neither ions react appreciably with water to form H⁺ and OH⁻, what is the solubility of this salt?
Q8486.The entropy and enthalpy of a system are a measure of
Adegree of disorderliness and heat content respectively
Bheat content and degree of disorderliness respectively
Cheat content of a system only
Ddegree of disorderliness only
Correct Answer: A
Entropy is a measure of the degree of disorderliness of a system. Enthalpy is a measure of the heat content of a system.
JAMB (UTME)
Chemistry
1996
Q8487.2SO₂(g) + O₂(g) ⇌ 2SO₃(g). In the chemical reaction above, the substance that will increase the rate of production of sulphur (VI) oxide is
Amanganese (IV) oxide
Bfinely divided iron
Cvanadium (V) oxide
Dnickel
Correct Answer: C
The contact process for the manufacture of sulphuric acid uses vanadium(V) oxide (V₂O₅) as a catalyst to oxidize SO₂ to SO₃.
JAMB (UTME)
Chemistry
1996
Q8488.N₂O₄(g) ⇌ 2NO₂(g). Increase in total pressure of the equilibrium reaction above will
Aproduce more of NO₂(g) in the mixture
Bconvert all of N₂O₄(g) to NO₂(g)
Chave no effect on the concentrations of N₂O₄(g) and NO₂(g)
Dproduce more of N₂O₄(g) in the mixture
Correct Answer: D
Increasing pressure shifts the equilibrium to the side with fewer gas molecules. The forward reaction produces 2 moles of gas from 1 mole, so the reverse reaction is favoured, producing more N₂O₄.
JAMB (UTME)
Chemistry
1996
Q8489.What quantity of electricity will liberate 0.125 mole of oxygen molecules during the electrolysis of dilute sodium chloride solution?
A24,125 coulombs
B48,250 coulombs
C72,375 coulombs
D96,500 coulombs
Correct Answer: B
4OH⁻ → O₂ + 2H₂O + 4e⁻. 1 mole of O₂ requires 4F = 4 × 96500 = 386,000 C. 0.125 mole requires 0.125 × 386,000 = 48,250 C.
JAMB (UTME)
Chemistry
1996
Q8490.When a current I was passed through an electrolyte solution for 40 minutes, a mass Xg of a univalent metal was deposited at the cathode. What mass of the metal will be deposited when a current 2I is passed through the solution for 10 minutes?
AX/4 g
BX/2 g
C2X g
D4X g
Correct Answer: B
Mass deposited is proportional to the quantity of electricity (Q = It). Original mass = X ∝ I × 40. New mass ∝ 2I × 10 = 20I. Ratio = 20/40 = 1/2. New mass = X/2.
JAMB (UTME)
Chemistry
1996
Q8491.R(s) + HF(aq) ⇌ RF(s) + HS(aq); ΔH = -65.7 kJ mol⁻¹. From the equation above, it can be deduced that
Athe heat content of the reactants is lower than that of the products
Bthe heat content of the reactants is higher than that of the products
Cthe reaction is slow
Da large amount of heat is absorbed
Correct Answer: B
The reaction is exothermic (ΔH = -65.7 kJ). In an exothermic reaction, the heat content of the reactants is higher than that of the products.
JAMB (UTME)
Chemistry
1996
Q8492.Which of the following statements is true of the electrochemical series?
AElectropositivity of metals increases down the series
BElectropositivity of non-metals decreases down the series
CElectronegativity of non-metals increases down the series
DElectropositivity of metals decreases down the series
Correct Answer: D
The electrochemical series arranges metals in order of decreasing reactivity (electropositivity) from top to bottom.
JAMB (UTME)
Chemistry
1996
Q8493.The gas that will form a white precipitate with acidified silver trioxonitrate (V) is
ANH₃
BSO₂
CCO₂
DHCl
Correct Answer: D
HCl gas reacts with acidified AgNO₃ to form a white precipitate of AgCl.
JAMB (UTME)
Chemistry
1996
Q8494.Chlorine, bromine and iodine resemble one another in that they
Adissolve in alkalis
Breact violently with hydrogen without heating
Care liquids
Ddisplace one another from solutions of their salts
Correct Answer: A
Halogens (Cl₂, Br₂, I₂) react with alkalis to form halides and hypohalites/halates. They are not all liquids (Cl₂ is gas, Br₂ is liquid, I₂ is solid). Only F₂ reacts violently with H₂ in the dark. A more reactive halogen can displace a less reactive one.
JAMB (UTME)
Chemistry
1996
Q8495.The salt that reacts with dilute hydrochloric acid to produce a pungent smelling gas which decolorizes acidified purple potassium tetraoxomanganate (VII) solution is
ANa₂SO₄
BNa₂SO₃
CNa₂S
DNa₂CO₃
Correct Answer: B
Na₂SO₃ reacts with HCl to produce SO₂ gas, which has a pungent smell and decolorizes acidified KMnO₄ solution.
JAMB (UTME)
Chemistry
1996
Q8496.A pair of compounds that can be used to generate a gas which has a physiological effect on human beings is
Asodium trioxonitrate (V) and calcium chloride
Bsodium dioxonitrate (III) and ammonium chloride
Csodium trioxonitrate (V) and ammonium chloride
Dsodium dioxonitrate (III) and potassium chloride
Correct Answer: B
Sodium dioxonitrate(III) (NaNO₂) and ammonium chloride (NH₄Cl) react to produce nitrogen gas (N₂). (Note: The question is unclear. If the gas is NH₃, then C is correct. If the gas is N₂, then B is correct. The provided answer B suggests N₂).
JAMB (UTME)
Chemistry
1996
Q8497.Hydrogen is used in oxy-hydrogen flames for melting metals because it
Aevolves a lot of heat when burnt
Bcombines explosively with oxygen
Cis a very light gas
Dis a rocket fuel
Correct Answer: A
The oxy-hydrogen flame produces a very high temperature (about 2500°C) due to the large amount of heat evolved when hydrogen burns in oxygen.
JAMB (UTME)
Chemistry
1996
Q8498.In the diagram above, Y is a mixture of
ACalcium hydroxide and ammonium chloride
BCalcium hydroxide and sodium chloride
CSodium chloride and ammonium trioxonitrate (V)
DSodium dioxonitrate (II) and ammonium chloride
Correct Answer: A
The setup is for the laboratory preparation of ammonia gas. It uses calcium hydroxide (slaked lime) and ammonium chloride.
JAMB (UTME)
Chemistry
1996
Q8499.What properties of duralumin make it more useful than its constituent metals?
AIt is heavy with a high melting point
BIt is malleable and has high density
CIt is strong and light
DIt is hard and ductile
Correct Answer: C
Duralumin (an alloy of aluminium, copper, magnesium, and manganese) is strong and lightweight, making it useful in aircraft construction.
JAMB (UTME)
Chemistry
1996
Q8500.The pair of metals in the reactivity series that are usually extracted by the electrolysis of their ores is
AMagnesium and zinc
BMagnesium and calcium
CCopper and zinc
DLead and calcium
Correct Answer: B
Very reactive metals like magnesium and calcium are extracted by the electrolysis of their molten ores.