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Instruction
JAMB Chemistry 1997
JAMB (UTME)
Chemistry
1997
Q8551.In the diagram above, the gas evolved is
ANH₃
BNO₂
CN₂O
DO₂
Correct Answer: A
The setup shows the heating of a mixture of NH₄Cl and Ca(OH)₂ to produce ammonia gas.
JAMB (UTME)
Chemistry
1997
Q8552.The IUPAC name for the compound CH₃CH₂CH₂Br is
A1-bromopropane
B2-bromopropane
C3-bromopropane
D1-bromobutane
Correct Answer: A
The compound is a 3-carbon chain with a bromine at position 1. It is 1-bromopropane.
JAMB (UTME)
Chemistry
1997
Q8553.Carbohydrates are compounds containing carbon, hydrogen and oxygen in the ratio
A3:1:1
B2:1:1
C1:2:1
D1:1:1
Correct Answer: C
The general formula for carbohydrates is Cₙ(H₂O)ₘ, so the ratio of C:H:O is 1:2:1.
JAMB (UTME)
Chemistry
1997
Q8554.How many isomers does pentane have?
A6
B5
C4
D3
Correct Answer: D
Pentane (C₅H₁₂) has three isomers: n-pentane, isopentane (2-methylbutane), and neopentane (2,2-dimethylpropane).
JAMB (UTME)
Chemistry
1997
Q8555.The leachate of a certain plant ash is used in local soap making because it contains
Asodium chloride
Bsodium hydroxide
Cpotassium hydroxide
Dcalcium hydroxide
Correct Answer: A
Plant ash contains potassium carbonate (potash), which is an alkali used in local soap making. (The provided answer E is a typo; the correct answer is C, potassium hydroxide, when dissolved in water).
JAMB (UTME)
Chemistry
1997
Q8556.The formula for ethyl butanoate is
AC₂H₅COOC₂H₅
BC₂H₅COOC₄H₉
CC₄H₉COOC₂H₅
DC₂H₅COOC₄H₉
Correct Answer: C
Ethyl butanoate is formed from ethanol (C₂H₅OH) and butanoic acid (C₄H₉COOH). The formula is C₄H₉COOC₂H₅.
JAMB (UTME)
Chemistry
1997
Q8557.The type of reaction that is peculiar to benzene is
Aaddition
Bhydrolysis
Cpolymerization
Dsubstitution
Correct Answer: D
Benzene undergoes electrophilic substitution reactions (e.g., nitration, halogenation) rather than addition reactions.
JAMB (UTME)
Chemistry
1997
Q8558.Ethanol reacts with excess acidified K₂Cr₂O₇ to give
Aethanedioic acid
Bethanal
Cethyl ethanoate
Dethanoic acid
Correct Answer: D
Excess acidified K₂Cr₂O₇ is a strong oxidizing agent that oxidizes ethanol to ethanoic acid.
JAMB (UTME)
Chemistry
1997
Q8559.A compound contains 40.0% carbon, 6.7% hydrogen and 53.3% oxygen. If the molar mass of the compound is 180, find the molecular formula.
ACH₂O
BC₃H₆O₃
CC₆H₁₂O₆
DC₆H₁₂O₆
Correct Answer: C
Moles ratio: C = 40/12 = 3.33, H = 6.7/1 = 6.7, O = 53.3/16 = 3.33. Ratio = 1:2:1. Empirical formula = CH₂O (M=30). n = 180/30 = 6. Molecular formula = C₆H₁₂O₆.
JAMB (UTME)
Chemistry
1997
Q8560.The process by which atoms are rearranged into different molecular structures in the petroleum refining process is referred to as
Acatalytic cracking
Bhydrocracking
Cpolymerization
Dreforming
Correct Answer: D
Reforming is the process of rearranging hydrocarbon molecules to improve their quality (e.g., converting straight-chain alkanes to branched-chain or aromatic compounds).
JAMB (UTME)
Chemistry
1997
Q8561.Which of the following is found in cotton?
AStarch
BCellulose
CFat
DOil
Correct Answer: B
Cotton is almost pure cellulose.
JAMB (UTME)
Chemistry
1997
Q8562.The principal constituent of natural gas is
Amethane
Bethane
Cpropane
Dbutane
Correct Answer: A
Natural gas is composed primarily of methane (CH₄).
Instruction
JAMB Chemistry 1998
JAMB (UTME)
Chemistry
1998
Q8563.The addition of water to calcium oxide leads to
Aa physical change
Ba chemical change
Cthe formation of a mixture
Dan endothermic change
Correct Answer: B
CaO + H₂O → Ca(OH)₂. This is a chemical change because a new substance (calcium hydroxide) is formed.
JAMB (UTME)
Chemistry
1998
Q8564.A mixture of iron and sulphur can be separated by dissolving the mixture in
Asteam
Bdilute hydrochloric acid
Cdilute sodium hydroxide
Dbenzene
Correct Answer: B
Iron dissolves in dilute HCl, while sulphur does not. Filtration can then separate the sulphur. (Note: Using a magnet is the simplest method, but if dissolving is required, HCl works).
JAMB (UTME)
Chemistry
1998
Q8565.8.0 g of an element X reacted with an excess of copper (II) tetraoxosulphate (VI) solution to deposit 21.3 g of copper. The correct equation for the reaction is
AX(s) + CuSO₄(aq) → Cu(s) + XSO₄(aq)
BX(s) + 2CuSO₄(aq) → 2Cu(s) + X(SO₄)₂(aq)
C2X(s) + CuSO₄(aq) → Cu(s) + X₂SO₄(aq)
D2X(s) + 3CuSO₄(aq) → 3Cu(s) + X₂(SO₄)₃(aq)
Correct Answer: A
Moles of Cu deposited = 21.3/64 = 0.333 mol. Moles of X = 8/M. For a 1:1 ratio (equation A), M = 8/0.333 = 24 (magnesium). This fits.
JAMB (UTME)
Chemistry
1998
Q8566.C₃H₈(g) + 5O₂(g) → 4H₂O(g) + 3CO₂(g). From the equation above, the volume of oxygen at s.t.p. required to burn 50 cm³ of propane is
A250 cm³
B150 cm³
C100 cm³
D50 cm³
Correct Answer: A
From the equation, 1 volume of propane requires 5 volumes of oxygen. 50 cm³ of propane requires 5 × 50 = 250 cm³ of oxygen.
JAMB (UTME)
Chemistry
1998
Q8567.30 cm³ of hydrogen was collected over water at 27°C and 780 mm Hg. If the vapour pressure of water at the temperature of the experiment was 10 mm Hg, calculate the volume of the gas at 760 mm Hg and 7°C.
A40.0 cm³
B35.7 cm³
C28.4 cm³
D25.2 cm³
Correct Answer: C
P₁ = 780 - 10 = 770 mm Hg, V₁ = 30 cm³, T₁ = 300 K. P₂ = 760 mm Hg, T₂ = 280 K. V₂ = (P₁V₁T₂)/(P₂T₁) = (770 × 30 × 280)/(760 × 300) = 28.4 cm³.
JAMB (UTME)
Chemistry
1998
Q8568.A given amount of gas occupies 10.0 dm³ at 4 atm. and 273°C. The number of moles of the gas present is
A0.089 mol
B1.90 mol
C3.80 mol
D5.70 mol
Correct Answer: A
Using ideal gas law: PV = nRT. P = 4 atm, V = 10.0 dm³, T = 273 + 273 = 546 K, R = 0.0821 dm³ atm K⁻¹ mol⁻¹. n = (4 × 10.0)/(0.0821 × 546) = 40/44.83 = 0.89 mol.
JAMB (UTME)
Chemistry
1998
Q8569.If sulphur (IV) oxide and methane are released simultaneously at the opposite ends of a narrow tube, the rates of diffusion R(SO₂) and R(CH₄) will be in the ratio
A4:1
B2:1
C1:2
D1:4
Correct Answer: C
Molar mass of SO₂ = 64, CH₄ = 16. Rate_SO₂/Rate_CH₄ = √(M_CH₄/M_SO₂) = √(16/64) = √(1/4) = 1/2. So the ratio is 1:2.
JAMB (UTME)
Chemistry
1998
Q8570.A solid begins to melt when
Aconstituent particles acquire a greater kinetic energy
Benergy of vibration of particles of the solid is less than the intermolecular forces
Cconstituent particles acquire energy above the average kinetic energy
Denergy of vibration of particles of the solid equals the intermolecular forces
Correct Answer: D
Melting occurs when the energy of vibration of the particles overcomes the intermolecular forces holding them in the solid lattice.
JAMB (UTME)
Chemistry
1998
Q8571.The diagram above represents an atom that can combine with chlorine to form
Aan ionic bond
Ba covalent bond
Ca dative bond
Da metallic bond
Correct Answer: A
The atom has 2 valence electrons (electronic configuration 2,8,2), so it is magnesium. It loses 2 electrons to form an ionic bond with chlorine.
JAMB (UTME)
Chemistry
1998
Q8572.Which of the following electron configurations indicates an atom with the highest ionization energy?
A2,8,7
B2,8,8,1
C2,8,8,2
D2,8,8,7
Correct Answer: A
Configuration 2,8,7 is chlorine, which has the highest ionization energy among the options because it is a non-metal and has a strong tendency to gain an electron.
JAMB (UTME)
Chemistry
1998
Q8573.The lines observed in the simple hydrogen spectrum are due to emission of
Aelectron from the atom
Benergy by proton transition
Cenergy by electron transition
Dneutrons from the atom
Correct Answer: C
The lines in the hydrogen spectrum are due to energy emitted when an electron transitions from a higher energy level to a lower energy level.
JAMB (UTME)
Chemistry
1998
Q8574.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
1998
Q8575.The property used in obtaining oxygen and nitrogen industrially from air is the
Aboiling point
Bdensity
Crate of diffusion
Dsolubility
Correct Answer: A
Oxygen and nitrogen are obtained from liquid air by fractional distillation, which relies on the difference in their boiling points.
JAMB (UTME)
Chemistry
1998
Q8576.Excess phosphorus was burnt in a gas jar and the residual gas passed successively over concentrated KOH solution and concentrated H₂SO₄ before being collected in a flask. The gases collected are
Acarbon (IV) oxide, nitrogen and the rare gases
Bnitrogen (IV) oxide and the rare gases
Cnitrogen and the rare gases
Dcarbon (IV) oxide, nitrogen (IV) oxide and the rare gases
Correct Answer: C
Phosphorus burns in air to remove oxygen. The remaining gas (mostly nitrogen) is passed over KOH to remove CO₂, and then over H₂SO₄ to dry it. The gas collected is nitrogen and the rare (noble) gases.
JAMB (UTME)
Chemistry
1998
Q8577.Potassium tetraoxomanganate (VII) is often added to impure water to
Areduce organic impurities
Breduce inorganic impurities
Cdestroy bacteria and algae
Dremove permanent hardness
Correct Answer: C
Potassium tetraoxomanganate(VII) (KMnO₄) is an oxidizing agent used in water treatment to destroy bacteria and algae and to oxidize organic impurities.
JAMB (UTME)
Chemistry
1998
Q8578.The soil around a battery manufacturing factory is likely to contain a high concentration of
ACa²⁺ salts
BPb²⁺ salts
CMg²⁺ salts
DAl³⁺ salts
Correct Answer: B
Lead-acid batteries contain lead. The soil around a battery factory is likely to be contaminated with lead (Pb²⁺) salts.
JAMB (UTME)
Chemistry
1998
Q8579.90.0 g of MgCl₂ was placed in 50.0 cm³ of water to give a saturated solution at 298 K. If the solubility of the salt is 8.0 mol dm⁻³ at the same temperature, what is the mass of the salt left undissolved at the given temperature?
A52.0 g
B58.5 g
C85.5 g
D88.5 g
Correct Answer: A
Molar mass of MgCl₂ = 24 + 71 = 95 g/mol. Maximum moles that can dissolve in 50 cm³ (0.05 dm³) = 8.0 × 0.05 = 0.4 mol. Mass that can dissolve = 0.4 × 95 = 38.0 g. Mass left undissolved = 90.0 - 38.0 = 52.0 g.
JAMB (UTME)
Chemistry
1998
Q8580.Soap leather is an example of a colloid in which a
Aliquid is dispersed in gas
Bsolid is dispersed in liquid
Cgas is dispersed in liquid
Dliquid is dispersed in liquid
Correct Answer: C
Soap lather is a foam, which is a colloid of a gas dispersed in a liquid. (The provided answer D is a typo).
JAMB (UTME)
Chemistry
1998
Q8581.The pH of a solution obtained by mixing 100 cm³ of a 0.1 M HCl solution with 100 cm³ of a 0.2 M solution of NaOH is
A1.3
B7.0
C9.7
D12.7
Correct Answer: D
Moles of HCl = 0.1 × 0.1 = 0.01 mol. Moles of NaOH = 0.2 × 0.1 = 0.02 mol. NaOH is in excess by 0.01 mol. Total volume = 200 cm³ = 0.2 dm³. [OH⁻] = 0.01/0.2 = 0.05 M. pOH = -log(0.05) = 1.3. pH = 14 - 1.3 = 12.7.
JAMB (UTME)
Chemistry
1998
Q8582.In the conduction of aqueous potassium tetraoxosulphate (VI) solution, the current carriers are the
Aions
Belectrons
Chydrated ions
Dhydrated electrons
Correct Answer: C
In aqueous solutions, ions are hydrated (surrounded by water molecules). These hydrated ions carry the current.
JAMB (UTME)
Chemistry
1998
Q8583.What volume of 0.1 mol dm⁻³ solution of tetraoxosulphate (VI) acid would be needed to dissolve 2.86 g of sodium trioxocarbonate (IV) decahydrate crystals?
Q8584.1.2 F of electricity are passed through electrolytic cells containing Na⁺, Cu²⁺ and Al³⁺ in series. How many moles of each metal would be formed at the cathode of each cell?
A0.6 mole of Na, 1.2 moles of Cu and 1.2 moles of Al
B1.2 moles of Na, 0.6 mole of Cu and 0.4 mole of Al
C1.3 moles of Na, 2.4 moles of Cu and 2.4 moles of Al
D1.2 moles of Na, 2.4 moles of Cu and 3.6 moles of Al
Q8585.What mass of gold is deposited during the electrolysis of gold (III) tetraoxosulphate (VI) when a current of 15 A is passed for 193 seconds?
A1.97 g
B3.94 g
C5.91 g
D19.70 g
Correct Answer: A
Q = It = 15 × 193 = 2895 C. Au³⁺ + 3e⁻ → Au. 3 × 96500 C deposits 197 g Au. Mass = (2895 × 197)/(3 × 96500) = 1.97 g.
JAMB (UTME)
Chemistry
1998
Q8586.Fe(s) + Cu²⁺(aq) → Fe²⁺(aq) + Cu(s). From the reaction above it can be inferred that
AFe is the oxidizing agent
BFe is reduced
CCu²⁺ loses electrons
DCu²⁺ is the oxidizing agent
Correct Answer: D
Cu²⁺ gains electrons (is reduced) and causes Fe to be oxidized. Therefore, Cu²⁺ is the oxidizing agent.
JAMB (UTME)
Chemistry
1998
Q8587.2FeCl₂(s) + Cl₂(g) → 2FeCl₃(g). The reducing agent in the reaction above is
AFeCl₂
BCl₂
CFeCl₃
DFe
Correct Answer: A
Fe²⁺ in FeCl₂ is oxidized to Fe³⁺ in FeCl₃, so FeCl₂ is the reducing agent. Cl₂ is the oxidizing agent.
JAMB (UTME)
Chemistry
1998
Q8588.The reaction that is accompanied by a decrease in entropy when carried out at constant temperature is
AN₂O₄ → 2NO₂
BN₂ + 3H₂ → 2NH₃
CCaCO₃ → CaO + CO₂
D2N₂H₄ → 3N₂ + 4H₂O
Correct Answer: B
Entropy decreases when the number of gas molecules decreases. In N₂ + 3H₂ → 2NH₃, 4 moles of gas become 2 moles, so entropy decreases.
JAMB (UTME)
Chemistry
1998
Q8589.32 g of anhydrous copper (II) tetraoxosulphate (VI) dissolved in 1 dm³ of water generated 13.0 kJ of heat. The heat of solution is
A26.0 kJ mol⁻¹
B65.0 kJ mol⁻¹
C130.0 kJ mol⁻¹
D260.0 kJ mol⁻¹
Correct Answer: B
Molar mass of CuSO₄ = 63.5 + 32 + 64 = 159.5 g/mol. Moles = 32/159.5 = 0.2 mol. Heat released = 13.0 kJ. Heat of solution per mole = 13.0/0.2 = 65.0 kJ mol⁻¹.
JAMB (UTME)
Chemistry
1998
Q8590.Mg²⁺(aq) + 2e⁻ → Mg(s); E° = -2.37 V
ACu(s)
BCd(s)
CZn(s)
DMg(s)
Correct Answer: D
The strongest reducing agent is the metal with the most negative standard electrode potential, which is Mg (-2.37 V).
JAMB (UTME)
Chemistry
1998
Q8591.In the diagram above, the activation energy for the backward reaction is
A+5 kJ
B+15 kJ
C+25 kJ
D+30 kJ
Correct Answer: C
From the diagram, the transition state is at 40 kJ and the products are at 15 kJ. Activation energy for the backward reaction = 40 - 15 = 25 kJ.
JAMB (UTME)
Chemistry
1998
Q8592.Z(g) → Z(g). In the equation above, the rate of formation of Z is found to be independent of the concentration of Y and to quadruple when the concentration of X is doubled. The rate equation for the reaction is
AR = k[X][Y]
BR = k[X]²[Y]
CR = k[X]²[Y]²
DR = k[X]²[Y]⁰
Correct Answer: D
The rate is independent of [Y] (zero order). The rate quadruples when [X] doubles, so the reaction is second order with respect to X. Rate = k[X]²[Y]⁰.
JAMB (UTME)
Chemistry
1998
Q8593.2Cl₂(g) + 2H₂O(g) ⇌ 4HCl(g) + O₂(g); ΔH = +115 kJ mol⁻¹. In the above equilibrium reaction, a decrease in temperature will
Afavour the reverse reaction
Bfavour the forward reaction
Chave no effect on the equilibrium state
Ddouble the rate of the reverse reaction
Correct Answer: A
The forward reaction is endothermic (ΔH positive). Decreasing the temperature favours the exothermic (reverse) reaction.
In all three reactions, ammonia reduces the other substance (CuO, Cl₂, O₂) and is itself oxidized to nitrogen. This demonstrates the reducing properties of ammonia.
JAMB (UTME)
Chemistry
1998
Q8595.A gas that turns a filter paper previously soaked in lead ethanoate solution black is
Ahydrogen chloride
Bhydrogen sulphide
Csulphur (IV) oxide
Dsulphur (VI) oxide
Correct Answer: B
Lead ethanoate paper turns black in the presence of hydrogen sulphide (H₂S) gas due to the formation of black lead(II) sulphide (PbS).
JAMB (UTME)
Chemistry
1998
Q8596.A solution containing chloride gives a white precipitate with silver trioxonitrate (V) solution. The precipitate will be insoluble in dilute
AHNO₃ but soluble in ammonia solution
BHNO₃ and in ammonia solution
CHCl but soluble in ammonia solution
DHCl and in ammonia solution
Correct Answer: A
AgCl is a white precipitate that is insoluble in dilute HNO₃ but soluble in ammonia solution.
JAMB (UTME)
Chemistry
1998
Q8597.In the experiment above, X could be a solution of
ASodium trioxonitrate (V) and ammonium chloride
BSodium trioxonitrate (III) and ammonium chloride
CLead (II) trioxonitrate (V) and copper turnings
DPotassium trioxonitrate (V) and copper turnings
Correct Answer: B
The setup is for the laboratory preparation of nitrogen gas. It uses sodium trioxonitrate(III) (NaNO₂) and ammonium chloride (NH₄Cl).
JAMB (UTME)
Chemistry
1998
Q8598.The oxide that remains unchanged when heated in hydrogen is
ACuO
BFe₂O₃
CPbO₂
DZnO
Correct Answer: D
ZnO is not reduced by hydrogen under normal heating conditions because zinc is more reactive than hydrogen. CuO, Fe₂O₃, and PbO₂ are reduced.
JAMB (UTME)
Chemistry
1998
Q8599.Which of the following is observed when a solution of iron (III) chloride is mixed with a solution of sodium hydroxide?
AA white precipitate is formed
BA reddish-brown precipitate is formed
CA green precipitate is formed
DNo visible reaction occurs
Correct Answer: B
FeCl₃ reacts with NaOH to form a reddish-brown precipitate of iron(III) hydroxide, Fe(OH)₃.
JAMB (UTME)
Chemistry
1998
Q8600.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.