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Instruction
JAMB Chemistry 2016
JAMB (UTME)
Chemistry
2016
Q6751.Which of the following compounds gives a yellow residue when heated and also reacts with aqueous sodium hydroxide to give a white gelatinous precipitate soluble in excess sodium hydroxide solution?
A(NH₄)₂CO₃
BZnCO₃
CAl₂(SO₄)₃
DPbCO₃
Correct Answer: B
ZnCO₃ gives a yellow residue (ZnO) when heated. It reacts with NaOH to give a white gelatinous precipitate of Zn(OH)₂, which dissolves in excess NaOH to form zincate.
JAMB (UTME)
Chemistry
2016
Q6752.The least easily oxidized of the metals below is
ACu
BNa
CZn
DAl
Correct Answer: A
Copper (Cu) is the least easily oxidized among the options because it is at the bottom of the reactivity series. Sodium, zinc, and aluminium are more reactive.
JAMB (UTME)
Chemistry
2016
Q6753.Which of the following chlorides would exhibit the least ionic character?
AMgCl₂
BCaCl₂
CLiCl
DAlCl₃
Correct Answer: D
AlCl₃ exhibits the least ionic character. The difference in electronegativity between Al and Cl is smaller than that of Mg, Ca, or Li with Cl. AlCl₃ is predominantly covalent.
JAMB (UTME)
Chemistry
2016
Q6754.Which of the following CANNOT be obtained by fractional distillation of petroleum?
AParaffin
BBitumen
CKerosene
DDiesel
Correct Answer: A
Paraffin wax is obtained from petroleum but not directly by fractional distillation. It is obtained from the residue after distillation. Bitumen, kerosene, and diesel are obtained by fractional distillation.
JAMB (UTME)
Chemistry
2016
Q6755.Which of the following is used as an antiknock in automobile engines?
Atetramethylsilane
Blead tetraethyl
CGlycerol
Dn-heptane
Correct Answer: B
Lead tetraethyl (tetraethyl lead, Pb(C₂H₅)₄) was used as an antiknock agent in petrol to improve octane rating.
JAMB (UTME)
Chemistry
2016
Q6756.The Avogadro number of 24g of magnesium is the same as that of
A1g of hydrogen molecules
B16g of oxygen molecules
C32g of Oxygen molecules
D35.5g of chlorine molecules
Correct Answer: C
24g of Mg = 1 mole. 32g of O₂ = 1 mole. The number of molecules in 1 mole is Avogadro's number. 1g of H₂ = 0.5 mole. 16g of O₂ = 0.5 mole. 35.5g of Cl₂ = 0.5 mole.
JAMB (UTME)
Chemistry
2016
Q6757.In an electrolyte set-up to protect iron from corrosion, the iron is
Amade the cathode
Bmade the anode
Cused with a metal of lower electropositive potential
Dinitially coated with tin
Correct Answer: A
In cathodic protection, iron is made the cathode, and a more reactive metal (like zinc or magnesium) is made the anode (sacrificial anode). This prevents iron from corroding.
JAMB (UTME)
Chemistry
2016
Q6758.The removal of rust from iron by treatment with tetraoxosulphate (VI) acid is based on the
Ahydrolysis of the iron
Breaction of acid with base
Coxidation of the rust
Ddehydration of the iron
Correct Answer: B
Rust (hydrated iron(III) oxide) is a base. It reacts with tetraoxosulphate(VI) acid (H₂SO₄) in an acid-base reaction to form soluble iron(III) sulphate, which is washed away.
JAMB (UTME)
Chemistry
2016
Q6759.The substance often used for vulcanization of rubber is
AChlorine
Bhydrogen peroxide
CSulphur
Dtetraoxosulphate (VI) acid
Correct Answer: C
Sulphur is used in the vulcanization of rubber. It forms cross-links between rubber polymer chains, making the rubber harder, stronger, and more durable.
JAMB (UTME)
Chemistry
2016
Q6760.Metals of the first transition series have special properties which are different from those of groups I and II elements because they have partially filled
As-orbitals
Bp-orbitals
Cd-orbitals
Df-orbitals
Correct Answer: C
Transition metals have partially filled d-orbitals, which give them special properties like variable oxidation states, complex formation, catalytic activity, and colour.
JAMB (UTME)
Chemistry
2016
Q6761.A particle that contains 11 protons, 12 neutrons and 10 electrons is probably a
ANeutral non-metal
Bmetallic ion
Cnon-metallic ion
Dneutral metal
Correct Answer: B
The particle has 11 protons (Na) and 10 electrons (lost 1 electron), so it is Na⁺, a metallic ion.
JAMB (UTME)
Chemistry
2016
Q6762.A catalyst increases the rate of a chemical reaction by providing a path that
Araises the activation energy
Bincreases the temperature
Clowers the activation energy
Dincreases the concentration
Correct Answer: C
A catalyst speeds up a reaction by providing an alternative pathway with a lower activation energy.
JAMB (UTME)
Chemistry
2016
Q6763.A metal M displaces Zinc from ZnCl₂ solution. This shows that
Aelectrons flow from Zinc to M
BM is more electropositive than Zinc
CM is more electronegative than Zinc
DZinc is more electropositive than M
Correct Answer: B
A metal can displace another from its salt solution if it is more electropositive (more reactive) than the other. So M is more electropositive than zinc.
JAMB (UTME)
Chemistry
2016
Q6764.Calculate the quantity of electricity in coulombs required to liberate 10g of copper from a copper compound. [Cu = 64, F = 96500 C mol⁻¹]
A32395.5
B30156.3
C60784.5
D15196.6
Correct Answer: B
Cu²⁺ + 2e⁻ → Cu. Moles of Cu = 10/64 = 0.15625 mol. Moles of electrons = 2 × 0.15625 = 0.3125 mol. Quantity of electricity = 0.3125 × 96500 = 30156.25 C ≈ 30156.3 C.
JAMB (UTME)
Chemistry
2016
Q6765.The IUPAC names for the compounds CH₃COOH and CH₂=CH₂ are respectively
Aacetic acid and ethane
Bethanoic acid and ethene
Cmethanoic acid and ethylene
Dethanol and ethene
Correct Answer: B
CH₃COOH is ethanoic acid. CH₂=CH₂ is ethene.
JAMB (UTME)
Chemistry
2016
Q6766.The boiling point of water is higher than that of methanol because
Awater is an oxide while methanol is an alcohol
Binter-molecular forces in water are stronger than those in methanol
CWater is an inorganic compound while methanol is organic
DWater is a compound while methanol is a covalent compound
Correct Answer: B
Water has stronger intermolecular hydrogen bonds than methanol because each water molecule can form up to four hydrogen bonds, while methanol can form fewer.
JAMB (UTME)
Chemistry
2016
Q6767.If an element X of atomic number Z and mass number Y is irradiated by an intense concentration of neutrons, the relevant nuclear equation is
Aᵞ_Z X + ¹₀n → ᵞ⁻¹_(Z+1)X
Bᵞ_Z X + ¹₀n → ᵞ⁺¹_Z X
Cᵞ_Z X + ¹₀n → ᵞ_(Z+1)X
Dᵞ_Z X + ¹₀n → ᵞ⁺¹_(Z-1)X
Correct Answer: B
When a nucleus absorbs a neutron, the mass number increases by 1 while the atomic number remains the same. The correct equation is ᵞ_Z X + ¹₀n → ᵞ⁺¹_Z X.
JAMB (UTME)
Chemistry
2016
Q6768.Powdering the reactant if solid
A1, 2 and 3
B1, 3 and 5
C2, 3 and 5
D3 and 4
Correct Answer: B
Factors that increase the rate of reaction include lowering activation energy (catalyst), increasing temperature, and increasing surface area (powdering solids). Conducting in gaseous state and removing products affect equilibrium, not necessarily rate.
JAMB (UTME)
Chemistry
2016
Q6769.An element with atomic number twelve is likely to be
Aelectrovalent with a valency of 1
Belectrovalent with a valency of 2
Ccovalent with a valency of 2
Dcovalent with valency of 4
Correct Answer: B
Atomic number 12 is magnesium (Mg). It has 2 valence electrons and forms electrovalent (ionic) compounds with a valency of 2 (Mg²⁺).
JAMB (UTME)
Chemistry
2016
Q6770.Which of the following physical properties decreases across the Periodic Table?
Aionization potential
BElectron affinity
CElectronegativity
DAtomic radius
Correct Answer: D
Atomic radius decreases across a period from left to right due to increasing nuclear charge pulling electrons closer.
JAMB (UTME)
Chemistry
2016
Q6771.If a gas occupies a container of volume 146cm³ at 18°C and 0.971 atm, its volume in cm³ at s.t.p is
Q6772.50cm³ of carbon (II) oxide was exploded with 150cm³ of air containing 20% oxygen by volume, which of the reactants was in excess?
ACarbon (II) oxide
BCarbon (IV) oxide
COxygen
DNitrogen
Correct Answer: C
Volume of O₂ in air = 20% × 150 = 30 cm³. The reaction is 2CO + O₂ → 2CO₂. 50 cm³ of CO requires 25 cm³ of O₂. Since 30 cm³ of O₂ is available, O₂ is in excess.
JAMB (UTME)
Chemistry
2016
Q6773.The formula CH₂O for ethanoic acid is regarded as its
Amolecular formula
Bgeneral formula
Cempirical formula
DStructural formula
Correct Answer: C
CH₂O is the empirical formula of ethanoic acid (CH₃COOH). The molecular formula is C₂H₄O₂.
JAMB (UTME)
Chemistry
2016
Q6774.The process of converting linear alkanes to branched chain and cyclic hydrocarbons by heating in the presence of a catalyst to improve the quality of petrol is referred to as
Arefining
Bcracking
Creforming
Dblending
Correct Answer: C
Reforming is the process of converting straight-chain alkanes into branched-chain and cyclic hydrocarbons (aromatics) to improve the octane rating of petrol.
JAMB (UTME)
Chemistry
2016
Q6775.The petroleum fraction that is used in heating furnaces in industries is
Adiesel oil
Bgasoline
Ckerosene
Dlubricating oil
Correct Answer: A
Diesel oil is used in industrial heating furnaces and diesel engines. Gasoline is for cars, kerosene for lamps and jet fuel, and lubricating oil for lubrication.
JAMB (UTME)
Chemistry
2016
Q6776.The polymer used in making car rear lights is
APerspex
BBakelite
Cpolystyrene
Dpolyacrylonitrile
Correct Answer: D
Polyacrylonitrile (PAN) is used in making car rear lights because it is transparent, strong, and heat-resistant.
JAMB (UTME)
Chemistry
2016
Q6777.Due to the unstable nature of ethyne, it is stored by dissolving in
Aethane-1,2-diol
Bpropanol
Cethanoic acid
Dpropanone
Correct Answer: D
Ethyne is stored by dissolving it in propanone (acetone) under pressure. This is because ethyne is unstable and can explode if compressed alone.
JAMB (UTME)
Chemistry
2016
Q6778.The process of converting starch to ethanol is
Acracking
Bdistillation
Cfermentation
Doxidation
Correct Answer: C
Fermentation is the process by which starch is converted to ethanol using yeast (zymase enzyme).
JAMB (UTME)
Chemistry
2016
Q6779.The alkanol obtained from the production of soap is
Apropanol
Bethanol
Cglycerol
Dmethanol
Correct Answer: C
Saponification of fats and oils produces soap and glycerol (propane-1,2,3-triol).
JAMB (UTME)
Chemistry
2016
Q6780.A hydrocarbon has an empirical formula CH and a vapour density of 39. Determine its molecular formula. [C = 12, H = 1]
AC₂H₆
BC₃H₈
CC₃H₄
DC₆H₆
Correct Answer: D
Empirical formula mass = 12 + 1 = 13. Molecular mass = 2 × vapour density = 2 × 39 = 78. n = 78/13 = 6. Molecular formula = (CH)₆ = C₆H₆.
JAMB (UTME)
Chemistry
2016
Q6781.Polystyrene is widely used as packaging materials for fragile objects during transportation because of its
Alightness
Blow density
Chigh density
Dhigh compressibility
Correct Answer: B
Polystyrene foam has very low density and is an excellent shock absorber, making it ideal for packaging fragile objects.
JAMB (UTME)
Chemistry
2016
Q6782.Ethyne is passed through a hot tube containing organo-nickel catalyst to produce
AIsoprene
Bpolythene
Cethanol
Dbenzene
Correct Answer: D
Ethyne (acetylene) undergoes cyclization when passed through a hot tube containing an organo-nickel catalyst to produce benzene.
JAMB (UTME)
Chemistry
2016
Q6783.The bleaching action of chlorine is effective due to the presence of
AHydrogen chloride
BWater
CAir
DOxygen
Correct Answer: B
Chlorine bleaches by oxidation in the presence of water. It reacts with water to form hypochlorous acid (HOCl), which is the active bleaching agent.
Instruction
JAMB Chemistry 2017
JAMB (UTME)
Chemistry
2017
Q6784.The flame used by welders in cutting metals is
Abutane gas flame
Bacetylene flame
CKerosene flame
DOxy-acetylene flame.
Correct Answer: D
Welders use the oxy-acetylene flame, which burns at a very high temperature (about 3000°C) and is suitable for cutting and welding metals.
JAMB (UTME)
Chemistry
2017
Q6785.At room temperature (300K) in Fig 1 below
AY is twice as soluble as X.
BX is twice as soluble as Y
CX and Y are soluble to the same extent
DX is three times as soluble as Y
Correct Answer: A
From the solubility graph, at 300 K, the solubility of Y is approximately twice that of X.
JAMB (UTME)
Chemistry
2017
Q6786.Tetraoxosulphate (VI) acid is prepared using the chemical reaction SO₃(g) + H₂O(l) → H₂SO₄(l). Given the heats of formation for SO₃(g), H₂O(l) and H₂SO₄(l) as -395 KJmol⁻¹, -286 KJmol⁻¹ and -811 KJmol⁻¹ respectively, the enthalpy change accompanying this reaction is
Q6787.In two separate experiments 0.36g and 0.71g of chlorine combined with a metal X to give Y and Z, an analysis showed that Y and Z contain 0.20g and 0.40g of X respectively. The data above represents the law of
Amultiple proportion
Bconservation of mass
Cconstant composition
Dreciprocal proportion.
Correct Answer: A
The law of multiple proportions states that when two elements combine to form more than one compound, the masses of one element that combine with a fixed mass of the other are in simple whole-number ratios. Here, the ratio of X in Y and Z is 0.20:0.40 = 1:2.
JAMB (UTME)
Chemistry
2017
Q6788.If an element X of atomic number Z and mass number Y is irradiated by an intense concentration of neutrons, the relevant nuclear equation is
Aᵞ_Z X + ¹₀n → ᵞ⁻¹_(Z+1)X
Bᵞ_Z X + ¹₀n → ᵞ⁺¹_Z X
Cᵞ_Z X + ¹₀n → ᵞ_(Z+1)X
Dᵞ_Z X + ¹₀n → ᵞ⁺¹_(Z-1)X
Correct Answer: B
When a nucleus absorbs a neutron, the mass number increases by 1 while the atomic number remains the same. The correct equation is ᵞ_Z X + ¹₀n → ᵞ⁺¹_Z X.
JAMB (UTME)
Chemistry
2017
Q6789.The vapour density of a gas may be defined as
Athe mass of a unit volume of the gas compared to an equal volume of water vapour.
Bthe mass of a unit volume of the gas compared to an equal volume of hydrogen.
Cthe mass of a unit volume of the gas compared to an equal volume of oxygen.
DThe mass of a unit volume of the gas minus the vapour pressure of water.
Correct Answer: B
Vapour density is the mass of a unit volume of a gas compared to the mass of an equal volume of hydrogen under the same conditions.
JAMB (UTME)
Chemistry
2017
Q6790.30cm³ of oxygen at 10 atmosphere pressure is placed in a 20dm³ container. Calculate the new pressure if temperature is kept constant.
Aits vapour pressure is equal to the vapour pressure of its solid at the given temperature
Bmolecules start escaping its surface
Cits vapour pressure equals the atmospheric pressure
Dits volume is slightly increased.
Correct Answer: C
A liquid boils when its saturated vapour pressure equals the external atmospheric pressure.
JAMB (UTME)
Chemistry
2017
Q6792.Four elements W, X, Y and Z have atomic numbers 2, 6, 16 and 20 respectively. Which of these elements is a metal?
AX
BW
CZ
DY
Correct Answer: C
Atomic number 20 is calcium (Ca), which is a metal. W (2) is helium, X (6) is carbon, Y (16) is sulphur.
JAMB (UTME)
Chemistry
2017
Q6793.When cathode rays are deflected unto the electrode of an electrometer, the instrument becomes
Apositively charged
Bnegatively charged
Cneutral
Dpositively and negatively charged
Correct Answer: B
Cathode rays are streams of electrons (negatively charged). When they hit an electrode, the electrode becomes negatively charged.
JAMB (UTME)
Chemistry
2017
Q6794.When large hydrocarbon molecules are heated at high temperature in the presence of a catalyst to give smaller molecules, the process is known as
Adisintegration
BPolymerization
Ccracking
Ddegradation
Correct Answer: C
Cracking is the process of breaking down large hydrocarbon molecules into smaller, more useful molecules using heat and a catalyst.
JAMB (UTME)
Chemistry
2017
Q6795.If concentrated sulphuric acid is added to sugar and warmed gently, the sugar changes from white to brown and finally to a black mass of carbon. In this reaction, concentrated sulphuric acid is acting as
Aa drying agent
Ban oxidizing agent
Ca dehydrating agent
Da reducing agent.
Correct Answer: C
Concentrated H₂SO₄ removes water from sugar (C₁₂H₂₂O₁₁), leaving behind black carbon. This is a dehydration reaction.
JAMB (UTME)
Chemistry
2017
Q6796.Smoke consists of
Asolid particles dispersed in liquid
Bsolid or liquid particles dispersed in gas
Cgas or liquid particles dispersed in liquid.
DLiquid particles dispersed in liquid.
Correct Answer: B
Smoke is an aerosol consisting of solid or liquid particles dispersed in a gas (usually air).
JAMB (UTME)
Chemistry
2017
Q6797.In the electrolysis of dilute sulphuric acid using platinum electrodes, the products obtained at the anode and cathode are:
Asulphur and hydrogen
Bhydrogen and oxygen
Coxygen and hydrogen
Dhydrogen and sulphate ions
Correct Answer: C
In the electrolysis of dilute H₂SO₄, O₂ is produced at the anode (oxidation of water) and H₂ at the cathode (reduction of water).
JAMB (UTME)
Chemistry
2017
Q6798.P(g) + Q(g) ⇌ 3R(s) + S(g) ΔH is negative.
AIncreasing the temperature
BRemoving some S
CAdding a catalyst
DDecreasing the pressure
Correct Answer: B
Removing some S (a product) will shift the equilibrium to the right (forward), increasing the yield of R.
JAMB (UTME)
Chemistry
2017
Q6799.The mass of silver deposited when a current of 10A passed through a solution of silver salt for 4830s is
A108.0g
B54.0g
C27.0g
D13.5g
Correct Answer: B
Q = It = 10 × 4830 = 48300 C. Ag⁺ + e⁻ → Ag. 96500 C deposits 108 g of Ag. Mass = (108 × 48300)/96500 = 54.0 g.