JAMB Chemistry 2001 past questions and answers

Use the graph below to answer questions 1 and 2.
If the gas is cooled, at what temperature will it start to condense?

1. A.125°C
2. B.150°C
3. C.175°C
4. D.250°C

Use the graph below to answer questions 1 and 2.
How long does it take all the solid to melt?

1. A.2.5 mins.
2. B.6.0 mins.
3. C.1.0 min.
4. D.3.0 mins.

25cm³ of a gas X contains Z molecules at 15°C and 75 mmHg. How many molecules will 25 cm³ of another gas Y contain at the same temperature and pressure?

1. A.2Y
2. B.2Z
3. C.Z
4. D.Y

What mass of water is produced when 8.0g of hydrogen reacts with excess oxygen? [H=1, O = 16]

1. A.36.0g
2. B.8.0g
3. C.72.0g
4. D.16.0g

A particle that contains 9 protons, 10 neutrons and 10 electrons is a

1. A.negative ion
2. B.positive ion
3. C.neutral atom of a non-metal
4. D.neutral atom of a metal.

Cancerous growths are cured by exposure to

1. A.γ-rays
2. B.β-rays
3. C.α-rays
4. D.x-rays

An oxide XO₂ has a vapour density of 32. What is the atomic mass of X?

1. A.32
2. B.20
3. C.14
4. D.12

Millikan's contribution to the development of atomic theory is the determination of

1. A.charge on electron
2. B.positive rays
3. C.charge to mass ratio
4. D.cathode rays.

Four elements W, X, Y, and Z have atomic number 2, 6, 16 and 20 respectively. Which of these elements is a metal?

1. A.X
2. B.W
3. C.Z
4. D.Y

An element X with relative atomic mass 16.2 contains two isotopes ¹⁶₈X with relative abundance of 90% and ^m₈X with relative abundance of 10%. The value of m is

1. A.16
2. B.18
3. C.12
4. D.14

The diagram above represents the formation of

1. A.a metallic bond
2. B.an electrovalent bond
3. C.a covalent bond
4. D.a coordinate covalent bond.

Which of the following statements is correct about the average kinetic energy of the molecules of a gas?

1. A.It increases with increase in pressure
2. B.It increases at constant pressure
3. C.It increases with increase in temperature
4. D.It increases with increase in volume.

The pollution from petroleum spillage in rivers and lakes can best be dispersed by

1. A.pouring detergents
2. B.passing of ships through the area
3. C.pouring organic solvents
4. D.evaporation

Deliquescent substances are used for

1. A.cooling
2. B.wetting
3. C.melting
4. D.drying

Use the solubility curves below to answer questions 15 and 16.
If 1 dm³ of a saturated solution of L at 60°C is cooled to 25°C, what amount in mole will separate out?

1. A.0.75
2. B.0.25
3. C.1.00
4. D.0.50

Use the solubility curves below to answer questions 15 and 16.
At what temperature are the solubilities of L and K the same?

1. A.82°C
2. B.75°C
3. C.100°C
4. D.90°C

Pure solvents are obtained by

1. A.distillation
2. B.condensation
3. C.extraction
4. D.evaporation

What is the decrease in volume of air when pyrogallol is shaken with 30.00cm³ of air?

1. A.15.00cm³
2. B.6.30cm³
3. C.0.63cm³
4. D.0.06cm³

Environmental pollution is worsened by the release from automobile exhausts of

1. A.water vapour
2. B.steam
3. C.smoke
4. D.heavy metals

The chemical used for coagulation in water purification is

1. A.aluminium tetraoxosulphate (VI)
2. B.copper tetraoxosulphate (VI)
3. C.sodium tetraoxosulphate (VI)
4. D.calcium tetraoxosulphate (VI)

Phosphorus is stored under water to prevent it from

1. A.dehydrating
2. B.becoming inert
3. C.smelling
4. D.catching fire.

In which of the following reactions does reduction take place?

1. A.Fe²⁺ − e⁻ → Fe³⁺
2. B.2O²⁻ → O₂ + 4e⁻
3. C.Cr − 2e⁻ → Cr²⁺
4. D.2H⁺ + 2e⁻ → H₂

P_(g) + Q_(g) ⇌ 3R_(s) + S_(g) ΔH is negative
Which of the following will increase the yield of R?

1. A.Using a larger closed vessel.
2. B.Increasing the temperature
3. C.Removing some S.
4. D.Adding a positive catalyst.

A metal M displaces zinc from zinc chloride solution. This shows that

1. A.M is more electronegative than zinc
2. B.zinc is above hydrogen in the series
3. C.M is more electropositive than zinc
4. D.electrons flow from zinc to M.

Which of the following best explains the increase in the rate of a chemical reaction as the temperature rises?

1. A.The bonds in the reacting molecules are more readily broken.
2. B.The molecular collisions become more violent.
3. C.A lower proportion of the molecules has the necessary minimum energy to react.
4. D.The collision frequency of the molecules increases.

What current in amperes will deposit 2.7g of aluminium in 2 hours? [Al = 27, F = 96 500 C mol⁻¹]

1. A.32
2. B.8
3. C.4
4. D.16

Ethanoic acid is

1. A.tribasic
2. B.unionizeable
3. C.monobasic
4. D.dibasic

C_(s) + 2S_(g) → CS_2(g) ΔH = +89 kJ mol⁻¹
The chemical equation above implies that

1. A.each of carbon and sulphur has 89kJ of energy
2. B.both carbon and sulphur contribute 89kJ of energy
3. C.89 kJ of energy is released
4. D.89 kJ of energy is absorbed

3Cu_(s) + 8HNO_3(aq) → 3Cu(NO₃)_2(aq) + 4H₂O_(l) + 2NO_(g)
In the equation above, copper is

1. A.an electron acceptor
2. B.a base
3. C.an oxidizing agent
4. D.a reducing agent

When ΔH is negative, a reaction is said to be

1. A.ionic
2. B.reversible
3. C.exothermic
4. D.endothermic

As the concentration of an electrolyte reduces, the conductivity

1. A.reduces to zero
2. B.decreases
3. C.increases
4. D.is unaffected

NH_3(g) + HCl_(g) → NH₄Cl_(s)
The entropy change in the system above is

1. A.negative
2. B.indeterminate
3. C.positive
4. D.zero

Fermentation is the

1. A.breaking down of carbohydrate to glucose
2. B.conversion of sugar to alcohol in the presence of yeast
3. C.breaking down of sugar to carbohydrate
4. D.conversion of alcohol to sugar in the presence of yeast.

The general formula for the alkanals is

1. A.ROH
2. B.R₂CO
3. C.RCOOR'
4. D.RCHO

The main impurity in iron ore during the extraction of iron is

1. A.silicon (IV) oxide
2. B.carbon (IV) oxide
3. C.calcium trioxosilicate
4. D.sulphur (II) oxide.

During the vulcanization of rubber, sulphur is added to

1. A.break down rubber polymer
2. B.lengthen the chain of rubber
3. C.bind rubber molecules together
4. D.act as a catalyst

Catalytic hydrogenation of benzene produces

1. A.oil
2. B.cyclohexene
3. C.cyclohexane
4. D.margarine

A trihydric alkanol is

1. A.glycerol
2. B.phenol
3. C.glycol
4. D.ethanol

When chlorine is passed into water and the resulting solution exposed to sunlight, the products formed are

1. A.chlorine gas and hydrogen
2. B.oxygen and oxochlorate (I) acid
3. C.chlorine gas and oxochlorate (I) acid
4. D.hydrochloric acid and oxygen

Proteins in acid solution undergo

1. A.polymerization
2. B.substitution
3. C.fermentation
4. D.hydrolysis

A characteristic reaction of the compounds with the general formula C_nH_2n is

1. A.esterification
2. B.polymerization
3. C.decarboxylation
4. D.substitution

The pair of organic compounds that are isomers is

1. A.benzene and methylbenzene
2. B.trichloromethane and tetrachloromethane
3. C.ethanol and propanone
4. D.but-l-ene and but-2-ene.

A burning candle produces water and

1. A.carbon (II) oxide
2. B.carbon (IV) oxide
3. C.oxygen
4. D.hydrogen

The gas that can best be collected by downward displacement of air is

1. A.chlorine
2. B.sulphur (IV) oxide
3. C.ammonia
4. D.carbon (IV) oxide.

Which of the following metals burns with a brick-red flame?

1. A.Pb
2. B.Ca
3. C.Na
4. D.Mg

Which of the following represents hybridization in ethyne?

1. A.sp²
2. B.sp²d
3. C.sp³
4. D.sp

C₁₂H₂₂O_11(s) + H₂SO_4(aq) → 12C_(s) + 11H₂O_(l) + H₂SO_4(aq)
In the reaction above, tetraoxosulphate (VI) acid functions as

1. A.a dehydrating agent
2. B.an oxidizing agent
3. C.a reducing agent
4. D.a catalyst

When sodium reacts with water, the resulting solution is

1. A.weakly acidic
2. B.neutral
3. C.acidic
4. D.alkaline