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Instruction
JAMB Chemistry 2003
JAMB (UTME)
Chemistry
2003
Q8851.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
2003
Q8852.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
2003
Q8853.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
2003
Q8854.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
2003
Q8855.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
2003
Q8856.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
2003
Q8857.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
2003
Q8858.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
2003
Q8859.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
2003
Q8860.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
2003
Q8861.Which of the following is found in cotton?
AStarch
BCellulose
CFat
DOil
Correct Answer: B
Cotton is almost pure cellulose.
JAMB (UTME)
Chemistry
2003
Q8862.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 2004
JAMB (UTME)
Chemistry
2004
Q8863.In the electrolysis of brine, the anode is
AZinc
BPlatinum
CCarbon
DCopper
Correct Answer: C
In the industrial electrolysis of brine (chlor-alkali process), carbon (graphite) is commonly used as the anode because it is inert and conducts electricity well.
JAMB (UTME)
Chemistry
2004
Q8864.N₂O₄(g) ⇌ 2NO₂(g)
Aa decrease in pressure
Ba decrease in volume
Can increase in pressure
Da constant volume
Correct Answer: A
The forward reaction produces 2 moles of gas from 1 mole. According to Le Chatelier's principle, decreasing pressure favours the side with more gas molecules (forward reaction). The reaction is also endothermic, so increasing temperature would favour it, but that option is not available.
JAMB (UTME)
Chemistry
2004
Q8865.The oxidation state of Chlorine in HClO₄ is
A-1
B5
C+7
D+1
Correct Answer: C
In HClO₄, H is +1, O is -2 (×4 = -8). Let Cl be x. +1 + x + (-8) = 0 → x = +7.
JAMB (UTME)
Chemistry
2004
Q8866.Which of the following hydrogen halides has the highest entropy value?
AHBr
BHF
CHI
DHCl
Correct Answer: C
Entropy increases with molecular mass and size. HI has the highest molecular mass among the hydrogen halides, so it has the highest entropy.
JAMB (UTME)
Chemistry
2004
Q8867.The mass of silver deposited when a current of 10A is passed through a solution of silver salt for 4830s is
A54.0 g
B27.0 g
C13.5 g
D108.0 g
Correct Answer: A
Q = It = 10 × 4830 = 48300 C. Ag⁺ + e⁻ → Ag. 96500 C deposits 108 g of Ag. Mass = (108 × 48300)/96500 = 54.0 g.
JAMB (UTME)
Chemistry
2004
Q8868.Which of the following acts as both a reducing and an oxidizing agent?
AH₂S
BSO₂
CNH₃
DCO₂
Correct Answer: B
SO₂ can act as a reducing agent (e.g., when oxidized to SO₃) and as an oxidizing agent (e.g., when reduced to S in reactions with H₂S).
JAMB (UTME)
Chemistry
2004
Q8869.Which of the following shows little or no net reaction when the volume of the system is decreased?
A2O₃(g) ⇌ 3O₂(g)
BH₂(g) + I₂(g) ⇌ 2HI(g)
C2NO₂(g) ⇌ N₂O₄(g)
DPCl₅(g) ⇌ PCl₃(g) + Cl₂(g)
Correct Answer: B
Decreasing volume (increasing pressure) favours the side with fewer gas molecules. In H₂ + I₂ ⇌ 2HI, there are 2 moles of gas on both sides, so pressure change has no effect.
JAMB (UTME)
Chemistry
2004
Q8870.Given that ΔH for the reaction 2CO(g) + O₂(g) → 2CO₂(g) is -566 kJ mol⁻¹ and ΔH for the reaction C(s) + O₂(g) → CO₂(g) is -394 kJ mol⁻¹, calculate ΔH for the reaction 2C(s) + O₂(g) → 2CO(g).
A normal salt is formed when all the replaceable hydrogen ions of an acid are replaced by a metal. Na₂CO₃ is a normal salt. NaHCO₃ and NaHSO₄ are acid salts.
JAMB (UTME)
Chemistry
2004
Q8890.A carcinogenic substance is
Anitrogen (II) oxide
Bcarbon (II) oxide
Casbestos dust
Dsawdust
Correct Answer: C
Asbestos dust is a known carcinogen that can cause lung cancer and mesothelioma.
JAMB (UTME)
Chemistry
2004
Q8891.What volume of 0.5 mol dm⁻³ H₂SO₄ will exactly neutralize 20 cm³ of 0.1 mol dm⁻³ NaOH solution?
Q8892.Calcium tetraoxosulphate (VI) dissolves in water only sparingly to form a
Acolloid
Bsolution
Csuspension
Dprecipitate
Correct Answer: B
Sparingly soluble salts dissolve to form a saturated solution.
JAMB (UTME)
Chemistry
2004
Q8893.Hardness of water is caused by the presence of the ions of
Acalcium and magnesium
Bcalcium and sodium
Cmagnesium and silver
Dsodium and potassium
Correct Answer: A
Hardness of water is caused by dissolved calcium (Ca²⁺) and magnesium (Mg²⁺) ions.
JAMB (UTME)
Chemistry
2004
Q8894.It is difficult to achieve an orderly arrangement of the molecules of a gas because they
Acan collide with one another in the container
Bare too small in size
Chave little force of attraction between them
Dhave no definite shape
Correct Answer: C
Gas molecules have weak intermolecular forces, so they move randomly and cannot be arranged orderly.
JAMB (UTME)
Chemistry
2004
Q8895.The shape of the s-orbital is
Aelliptical
Bspiral
Ccircular
Dspherical
Correct Answer: D
The s-orbital is spherical in shape.
JAMB (UTME)
Chemistry
2004
Q8896.Which of the following mixtures of gases is likely to burn in flame?
AHelium and neon
BNeon and nitrogen
CNeon and hydrogen
DNitrogen and helium
Correct Answer: C
Hydrogen is combustible. A mixture of hydrogen with an inert gas can burn.
JAMB (UTME)
Chemistry
2004
Q8897.The property of chlorine which causes hydrogen chloride to be more ionic than the chlorine molecule is its
Aelectronegativity
Belectropositivity
Celectron affinity
Delectrovalency
Correct Answer: A
Chlorine's high electronegativity creates a polar bond with hydrogen, giving HCl ionic character in aqueous solution.
JAMB (UTME)
Chemistry
2004
Q8898.In the experiment above, X is a mixture of nitrogen, carbon (IV) oxide and
Aoxygen
Binert gas
Cwater
Dimpurities
Correct Answer: B
The question is incomplete without the diagram. In the preparation of nitrogen from air, CO₂ is removed by KOH, O₂ by pyrogallol, and water vapour by CaCl₂. The remaining gas is nitrogen and inert gases.
JAMB (UTME)
Chemistry
2004
Q8899.A given volume of methane diffuses in 20s. How long will it take the same volume of sulphur (VI) oxide to diffuse under the same conditions?
A40s
B60s
C20s
D5s
Correct Answer: B
Molar mass of CH₄ = 16, SO₂ = 64. Rate_CH₄/Rate_SO₂ = √(M_SO₂/M_CH₄) = √(64/16) = 2. Time ratio is inverse: t_SO₂/t_CH₄ = 2. t_SO₂ = 2 × 20 = 40s. (The provided answer B is a typo).
JAMB (UTME)
Chemistry
2004
Q8900.Chlorine consisting of two isotopes of mass numbers 35 and 37 in the ratio 3:1 has an atomic mass of 35.5. Calculate the relative abundance of the isotope of mass number 37.
A60
B20
C75
D25
Correct Answer: D
Let abundance of Cl-37 be x, then Cl-35 is (100-x). The ratio 3:1 gives (100-x)/x = 3. 100-x = 3x. 4x = 100. x = 25%.