Q8153.In comparing the camera and human eye, the film of the camera functions as the
AIris
BPupil
CRetina
DCornea
Correct Answer: C
The film in a camera captures the image, just as the retina in the human eye receives the image.
JAMB (UTME)
Physics
2004
Q8154.What is the least possible error encountered when taking measurement with a meter rule?
A$0.5 \mathrm{mm}$
B$1.0 \mathrm{mm}$
C$0.2 \mathrm{mm}$
D$0.1 \mathrm{mm}$
Correct Answer: A
The least count of a metre rule is $1 \mathrm{mm}$, so the least possible error is half of the least count, which is $0.5 \mathrm{mm}$.
JAMB (UTME)
Physics
2004
Q8155.The electromotive force in the secondary winding is
Astabilizing
Breducing
Cincreasing
Dvarying
Correct Answer: D
In a transformer, the induced e.m.f. in the secondary winding varies with time (a.c.).
JAMB (UTME)
Physics
2004
Q8156.If a pump is capable of lifting $5000 \mathrm{kg}$ of water through a vertical height of $60 \mathrm{m}$ in $15 \mathrm{min}$, the power of the pump is
Q8157.Calculate the temperature change when $500 \mathrm{J}$ of heat is supplied to $100 \mathrm{g}$ of water. [Specific heat capacity of water $= 4200 \mathrm{Jkg}^{-1}\mathrm{K}^{-1}$]
Q8158.Which of the following particles CANNOT be deflected by both electric and magnetic fields?
AGamma rays
BAlpha particles
CWave particles
DBeta particles
Correct Answer: A
Gamma rays are electromagnetic waves with no charge, so they are not deflected by electric or magnetic fields.
JAMB (UTME)
Physics
2004
Q8159.Under which of the following conditions do gasses conduct electricity?
AHigh pressure and low p.d
BLow pressure and high p.d
CLow pressure and low p.d
DHigh pressure and high p.d
Correct Answer: B
Gases conduct electricity at low pressure and high potential difference.
JAMB (UTME)
Physics
2004
Q8160.Dispersion occurs when white light passes through a glass prism because of the
Adefects in the glass
Bhigh density of the glass
Cdifferent speeds of the colours in the glass
Ddifferent hidden colours in the glass
Correct Answer: C
Dispersion occurs because different colours of light travel at different speeds in a medium like glass.
JAMB (UTME)
Physics
2004
Q8161.Calculate the e.m.f of the cell in the above circuit if its internal resistance is negligible.
A$12 \mathrm{V}$
B$36 \mathrm{V}$
C$2 \mathrm{V}$
D$8 \mathrm{V}$
Correct Answer: A
The two resistors ($3\Omega$ and $6\Omega$) are in parallel. $\dfrac{1}{R} = \dfrac{1}{3} + \dfrac{1}{6} = \dfrac{1}{2}$. $R = 2\Omega$. $E = IR = 4 \times 2 = 8 \mathrm{V}$. The answer key A is incorrect; the correct answer is D ($8 \mathrm{V}$).
JAMB (UTME)
Physics
2004
Q8162.An object of mass $80 \mathrm{kg}$ is pulled on a horizontal rough ground by a force of $500 \mathrm{N}$. Find the coefficient of static friction. $[g \approx 10 \mathrm{ms}^{-2}]$
Q8163.The diagram above shows plank RS pivoted at its centre of gravity O and is in equilibrium with the weights P and Q. If a weight 2P is added to P, the plank will be in equilibrium again by
Amoving P nearer to O
Bmoving Q nearer to O
Cadding a weight Q to Q
Dmoving P further away from O
Correct Answer: B
Adding weight to P increases the anticlockwise moment. To restore equilibrium, Q must be moved further from O, or the moment on Q's side must increase. The answer key B is incorrect; moving Q nearer to O would decrease its moment. The correct action is to move Q further from O, or move P nearer to O. The closest correct option is A (moving P nearer to O).
Instruction
JAMB Chemistry 1990
JAMB (UTME)
Chemistry
1990
Q8164.A brand of ink containing cobalt (II), copper (II) and iron ions can best be separated into its various components by
Afractional crystallization
Bfractional distillation
Csublimation
Dchromatography
Correct Answer: D
Chromatography is the best method for separating a mixture of ions in solution, especially when they have similar solubilities. It separates components based on their different rates of migration through a stationary phase.
JAMB (UTME)
Chemistry
1990
Q8165.Which of the following substances is a mixture?
AGranulated sugar
BSea-water
CSodium chloride
DIron filings
Correct Answer: B
Sea-water is a mixture of water and dissolved salts. Granulated sugar, sodium chloride, and iron filings are pure substances (compounds or elements).
JAMB (UTME)
Chemistry
1990
Q8166.The number of molecules of carbon (IV) oxide produced when 10.0g CaCO₃ is treated with 0.2 dm³ of 1 M HCl in the equation CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂ is
A1.00 × 10²³
B6.02 × 10²³
C6.02 × 10²²
D6.02 × 10²⁴
Correct Answer: C
Moles of CaCO₃ = 10.0/100 = 0.1 mol. Moles of HCl = 0.2 × 1 = 0.2 mol. The reaction requires 2 moles of HCl per mole of CaCO₃, so HCl is the limiting reactant. Moles of CO₂ produced = 0.2/2 = 0.1 mol. Number of molecules = 0.1 × 6.02 × 10²³ = 6.02 × 10²².
JAMB (UTME)
Chemistry
1990
Q8167.In the reaction CaC₂ + 2H₂O → Ca(OH)₂ + C₂H₂, what is the mass of solid acetylene gas at s.t.p?
A3.8g
B2.9g
C2.0g
D1.0g
Correct Answer: B
The question asks for the mass of acetylene (C₂H₂) gas. At s.t.p., 1 mole of gas occupies 22.4 dm³. The question is incomplete without knowing the mass of CaC₂ used.
JAMB (UTME)
Chemistry
1990
Q8168.If the quantity of oxygen occupying a 2.76 litre container at a pressure of 0.825 atmosphere and 300 K is reduced by one-half, what is the pressure exerted by the remaining gas?
A1.650 atm
B0.825 atm
C0.413 atm
D0.275 atm
Correct Answer: C
Using the ideal gas law PV = nRT, if the volume and temperature are constant, pressure is directly proportional to the number of moles (P ∝ n). If the quantity of gas is reduced by half, the pressure is also reduced by half. P₂ = 0.825/2 = 0.413 atm.
JAMB (UTME)
Chemistry
1990
Q8169.Which of the following substances has the lowest vapour density?
AEthanoic acid
BPropanol
CDichloromethane
DEthanal
Correct Answer: D
Vapour density is proportional to molecular mass. Ethanoic acid (60), propanol (60), dichloromethane (85), ethanal (44). Ethanal has the lowest molecular mass and hence the lowest vapour density.
JAMB (UTME)
Chemistry
1990
Q8170.If d represents the density of a gas and K is a constant, the rate of gaseous diffusion is related to the equation
Ar = k/d
Br = kd
Cr = k/√d
Dr = k√d
Correct Answer: C
According to Graham's law of diffusion, the rate of diffusion (r) is inversely proportional to the square root of the density (d). Therefore, r = k/√d.
JAMB (UTME)
Chemistry
1990
Q8171.An isotope has an atomic number of 17 and a mass number of 36. Which of the following gives the correct number of neutrons and protons in an atom of the isotope?
ANeutrons = 53, Protons = 17
BNeutrons = 17, Protons = 17
CNeutrons = 19, Protons = 17
DNeutrons = 36, Protons = 17
Correct Answer: C
Protons = atomic number = 17. Neutrons = mass number - atomic number = 36 - 17 = 19.
JAMB (UTME)
Chemistry
1990
Q8172.The atomic numbers of two elements X and Y are 12 and 9 respectively. The bond in the compound formed between the atoms of these two elements is
Aionic
Bcovalent
Cneutral
Dco-ordinate
Correct Answer: A
Element X (atomic number 12) is magnesium, a metal. Element Y (atomic number 9) is fluorine, a non-metal. The bond formed between a metal and a non-metal is ionic (electrovalent).
JAMB (UTME)
Chemistry
1990
Q8173.An element Z contained 90% of ¹⁶₈Z and 10% of ¹⁸₈Z. Its relative atomic mass is
Q8174.The greater the difference in electronegativity between bonded atoms, the
Alower the polarity of the bond
Bhigher the polarity of the bond
Cweaker the bond
Dhigher the possibility of the substance formed being a molecule
Correct Answer: B
The greater the difference in electronegativity, the more polar the bond is. If the difference is large enough (>1.7), the bond becomes ionic.
JAMB (UTME)
Chemistry
1990
Q8175.A stream of air was successively passed through three tubes X, Y, and Z containing a concentrated aqueous solution of KOH, red hot copper powder and fused calcium chloride respectively. What was the composition of gas emanating from tube Z?
ACO₂ and the inert gases
BN₂, CO and the inert gases
CN₂ and the inert gases
DWater vapour, N₂ and the inert gases
Correct Answer: C
KOH absorbs CO₂. Red hot copper absorbs O₂. Fused CaCl₂ absorbs water vapour. The remaining gas is nitrogen and the inert (noble) gases.
JAMB (UTME)
Chemistry
1990
Q8176.In the purification of town water supply, alum is used principally to
Akill bacteria
Bcontrol the pH of water
Cimprove the taste of the water
Dcoagulate small particles of mud
Correct Answer: D
Alum (aluminium sulphate) is used as a coagulant. It causes small particles of mud and other impurities to clump together (coagulate) so they can be filtered out.
JAMB (UTME)
Chemistry
1990
Q8177.Which of the following water samples will have the highest titer value when titrated for the Ca²⁺ ions using soap solution?
APermanently hard water after boiling
BTemporarily hard water after boiling
CRain water stored in a glass jar for two years
DPermanently hard water passed through permutit
Correct Answer: A
Permanently hard water contains dissolved calcium and magnesium sulphates/chlorides that are not removed by boiling. It will therefore require the most soap to lather (highest titer value).
JAMB (UTME)
Chemistry
1990
Q8178.Oil spillage in ponds and creeks can be cleaned up by
Aburning off the oil layer
Bspraying with detergent
Cdispersal with compressed air
Dspraying with hot water
Correct Answer: B
Spraying with detergent helps to break up the oil slick into small droplets (dispersion), which can then be degraded by bacteria. Burning causes air pollution.
JAMB (UTME)
Chemistry
1990
Q8179.The solubility of Na₂HAsO₄·12H₂O is 38.9g per 100g H₂O. What is the percentage of Na₂HAsO₄ in the saturated solution?
A87.2%
B38.9%
C19.1%
D13.7%
Correct Answer: C
Mass of solution = 100 + 38.9 = 138.9 g. Percentage of Na₂HAsO₄ in the hydrated salt = (Na₂HAsO₄ molar mass) / (Na₂HAsO₄·12H₂O molar mass) × 100. Assuming complete dehydration, this is complex. The question likely asks for the percentage of the solute in the saturated solution. Mass of solute (hydrated) = 38.9 g. Total mass = 138.9 g. Percentage = 38.9/138.9 × 100 = 28%. (The provided answer C is a typo).
JAMB (UTME)
Chemistry
1990
Q8180.Which is the correct set results for tests conducted respectively on fresh lime and ethanol?
AFresh lime: Add crystals of NaHCO₃ - Gas evolved; Ethanol: No gas evolved
BFresh lime: Test with methyl orange - Turns colourless; Ethanol: No change
CFresh lime: Taste - Bitter; Ethanol: Sour
DFresh lime: Add a piece of sodium - No gas evolved; Ethanol: H₂ evolved
Correct Answer: A
Fresh lime contains citric acid, which reacts with NaHCO₃ to evolve CO₂ gas. Ethanol does not react with NaHCO₃.
JAMB (UTME)
Chemistry
1990
Q8181.In which of the following are the aqueous solutions of each of the substances correctly arranged in order of decreasing acidity?
AEthanoic acid, milk of magnesia, sodium chloride, hydrochloric acid and sodium hydroxide
BEthanoic acid, hydrochloric acid, milk of magnesia, sodium chloride and sodium hydroxide
CHydrochloric acid, ethanoic acid, sodium chloride, milk of magnesia and sodium hydroxide
DHydrochloric acid, sodium hydroxide, sodium chloride, ethanoic acid and milk of magnesia
Q8182.The basicity of tetraoxophosphate (V) acid is
A7
B5
C4
D3
Correct Answer: D
Tetraoxophosphate(V) acid is H₃PO₄. It has three replaceable hydrogen atoms, so its basicity is 3.
JAMB (UTME)
Chemistry
1990
Q8183.If 24.83 cm³ of 0.15 M NaOH is titrated to its end point with 39.45 cm³ of HCl, what is the molarity of the HCl?
A0.094 M
B0.150 M
C0.940 M
D1.500 M
Correct Answer: A
Moles of NaOH = 0.15 × 24.83/1000 = 0.0037245 mol. At endpoint, moles of HCl = moles of NaOH = 0.0037245 mol. Molarity of HCl = 0.0037245 / (39.45/1000) = 0.0944 M ≈ 0.094 M.
JAMB (UTME)
Chemistry
1990
Q8184.A quantity of electricity liberates 3.6 g of silver from its salt. What mass of aluminium will be liberated from its salt by the same quantity of electricity?
A2.7 g
B1.2 g
C0.9 g
D0.3 g
Correct Answer: D
Equivalent mass of Ag = 108/1 = 108. Equivalent mass of Al = 27/3 = 9. Mass of Al = (3.6/108) × 9 = 0.3 g.
JAMB (UTME)
Chemistry
1990
Q8185.Which of the following statements is CORRECT if 1 Faraday of electricity is passed through 1 M CuSO₄ solution for 1 minute?
AThe pH of the solution at the cathode decreases
BThe pH of the solution at the anode decreases
C1 mole of Cu will be liberated at the cathode
D60 moles of Cu will be liberated at the anode
Correct Answer: B
At the anode, OH⁻ ions are discharged, producing O₂ and H⁺ ions. The concentration of H⁺ increases, so the pH at the anode decreases. 1 Faraday deposits 0.5 mol of Cu.
JAMB (UTME)
Chemistry
1990
Q8186.What mass of magnesium would be obtained by passing a current of 2 amperes for 2 hrs. 30 mins through molten magnesium chloride?
A1.12 g
B2.00 g
C2.24 g
D4.48 g
Correct Answer: C
Q = It = 2 × (2 × 3600 + 30 × 60) = 2 × 9000 = 18000 C. Mg²⁺ + 2e⁻ → Mg. 2 × 96500 C deposits 24 g of Mg. Mass = (18000 × 24) / (2 × 96500) = 2.24 g.
JAMB (UTME)
Chemistry
1990
Q8187.In the reaction of 3CuO + 2NH₃ → 3Cu + 3H₂O + N₂, how many electrons are transferred for each mole of copper produced?
A4.0 × 10⁻²³
B3.0 × 10⁻²³
C1.2 × 10²⁴
D6.0 × 10²⁴
Correct Answer: C
Cu²⁺ + 2e⁻ → Cu. Each mole of Cu produced requires 2 moles of electrons. 2 × 6.02 × 10²³ = 1.2 × 10²⁴ electrons.
JAMB (UTME)
Chemistry
1990
Q8188.Z is a solid substance, which liberates carbon (IV) oxide on treatment with concentrated H₂SO₄ and decolorizes KMnO₄. The solid substance, Z is
Asodium hydrogen trioxocarbonate (IV)
Bethanoic acid
Ciron (II) trioxocarbonate (IV)
Dethanedioic acid (oxalic acid)
Correct Answer: D
Ethanedioic acid (oxalic acid) reacts with concentrated H₂SO₄ to produce CO, CO₂, and H₂O. It also decolorizes KMnO₄ (a strong oxidizing agent).
JAMB (UTME)
Chemistry
1990
Q8189.5 g of ammonium trioxonitrate (V) on dissolution in water cooled its surrounding water and container by 1.6 kJ. What is the heat of solution of NH₄NO₃?
Q8190.Tetraoxosulphate (VI) acid is prepared using the chemical reaction SO₃(g) + H₂O(l) → H₂SO₄(l). Given the heat of formation for SO₃(g), H₂O(l) and H₂SO₄(l) as -395 kJ mol⁻¹, -286 kJ mol⁻¹ and -811 kJ mol⁻¹ respectively, the enthalpy change is
Q8191.The times taken for iodine to be liberated in the reaction between sodium thiosulphate and hydrochloric acid at various temperatures are as follows:
Afor a 10° rise in temperature rate of reaction is doubled
Bfor a 10° rise in temperature rate of reaction is halved
Ctime taken for iodine to appear does not depend on temperature
Dfor a 10° rise in temperature, rate of reaction is tripled
Correct Answer: A
As temperature increases by 10°C (from 25 to 35, and 35 to 45), the time taken is halved (72 → 36 → 18). This means the rate of reaction is doubled.
JAMB (UTME)
Chemistry
1990
Q8192.The reaction between sulphur (IV) oxide and oxygen is represented by the equilibrium reaction 2SO₂(g) + O₂(g) ⇌ 2SO₃(g); ΔH = -196 kJ. What factor would influence increased production of SO₃(g)?
AAddition of a suitable catalyst
BIncrease in the temperature of the reaction
CDecrease in the temperature of SO₃(g)
DDecrease in the concentration of SO₃(g)
Correct Answer: A
A catalyst increases the rate of both forward and backward reactions equally, but it does not affect the equilibrium position. To increase the yield of SO₃, you would need to decrease the temperature (exothermic reaction) or increase pressure. (The provided answer A is a typo; a catalyst does not increase yield, only the rate of attainment of equilibrium).
JAMB (UTME)
Chemistry
1990
Q8193.Which of the following equations correctly represents the action of hot concentrated alkaline solution on chlorine?
Hot concentrated alkali reacts with chlorine to form chlorate(V) and chloride: 3Cl₂ + 6OH⁻ → ClO₃⁻ + 5Cl⁻ + 3H₂O.
JAMB (UTME)
Chemistry
1990
Q8194.Magnesium ribbon was allowed to burn inside a given gas P leaving a white solid residue Q. Addition of water to Q liberated a gas which produced dense white fumes with a drop of hydrochloric acid. The gas P was
Anitrogen
Bchlorine
Coxygen
Dsulphur (IV) oxide
Correct Answer: A
Magnesium burns in nitrogen to form magnesium nitride (Mg₃N₂). Mg₃N₂ reacts with water to produce ammonia (NH₃), which forms dense white fumes of NH₄Cl with HCl.
JAMB (UTME)
Chemistry
1990
Q8195.The best treatment for a student who accidentally poured concentrated tetraoxosulphate (VI) acid on his skin in the laboratory is to wash the skin with
Acold water
Bsodium trioxocarbonate (IV) solution
Ciodine solution
Dsodium trioxocarbonate (IV) solution
Correct Answer: B
Concentrated H₂SO₄ is a strong acid. It should be neutralized with a mild base like sodium trioxocarbonate(IV) (Na₂CO₃) solution, then washed with plenty of water.
JAMB (UTME)
Chemistry
1990
Q8196.In which of the following pairs of elements is allotropy exhibited by each element?
APhosphorus and hydrogen
BOxygen and chlorine
CSulphur and nitrogen
DOxygen and sulphur
Correct Answer: D
Both oxygen (O₂ and O₃) and sulphur (rhombic, monoclinic, plastic) exhibit allotropy.
JAMB (UTME)
Chemistry
1990
Q8197.Which of the following gases can best be used for demonstrating the fountain experiment?
A(ii) and (iii)
B(i) and (ii)
C(ii) and (iv)
D(ii) only
Correct Answer: C
Ammonia (NH₃) and hydrogen chloride (HCl) are highly soluble in water and are used in the fountain experiment to demonstrate their high solubility.
JAMB (UTME)
Chemistry
1990
Q8198.When calcium hydroxide is heated with ammonium tetraoxosulphate (VI), the gas given off may be collected by
Abubbling it through concentrated H₂SO₄
Bbubbling it through water and then passing it through calcium oxide
Cpassing it directly through calcium oxide
Dpassing it directly through calcium chloride
Correct Answer: C
The gas given off is ammonia (NH₃). It is a base and reacts with H₂SO₄. It is highly soluble in water. It is dried by passing through calcium oxide (a basic drying agent). Calcium chloride forms a complex with ammonia, so it is not suitable.
JAMB (UTME)
Chemistry
1990
Q8199.Which of the following elements will form oxide which will dissolve both dilute HNO₃ and NaOH solution to form salts?
ACl
BMg
CAg
DMn
Correct Answer: A
An oxide that dissolves in both acid and base is amphoteric. Examples include Al₂O₃, ZnO, PbO. Among the options, Al (not listed) is amphoteric. (The provided options do not contain the correct answer).
JAMB (UTME)
Chemistry
1990
Q8200.Stainless steel is an alloy of
Airon, carbon and silver
Biron, carbon and lead
Ciron, carbon and chromium
Diron and carbon only
Correct Answer: C
Stainless steel is an alloy of iron, carbon, and chromium (and often nickel).