JAMB Chemistry 2008 past questions and answers

Chlorophyll obtained from given leaves of plant can be shown to be composed of more than one coloured component by the technique of

1. A.crystallization
2. B.hydrolysis
3. C.chromatography
4. D.sublimation.

In countries where the temperature falls below 273K, salt is always sprinkled on the icy roads in order to

1. A.lower the melting point of the ice
2. B.increase the density of the ice
3. C.make the ice impure
4. D.raise the melting point of the ice.

2Na_(s) + 2H₂O_(l) → 2NaOH_(aq) + H_2(g)
From the equation above, calculate the mass of sodium hydroxide produced by 2.3g of sodium. [H = 1, O = 16, Na = 23]

1. A.0.40g
2. B.0.80g
3. C.4.00g
4. D.8.00g.

16.8g of sodium hydrogen trioxocarbonate (IV) is completely decomposed by heat. Calculate the volume of carbon (IV) oxide given off at s.t.p [Na = 23, C = 12, O = 16, H = 1, Molar volume of a gas at s.t.p. = 22.4 dm³]

1. A.22.40 dm³
2. B.11.20 dm³
3. C.2.24 dm³
4. D.1.12 dm³.

300 cm³ of a gas has a pressure of 800 mm Hg. If the pressure is reduced to 650 mm Hg, find its volume.

1. A.243.75 cm³
2. B.369.23 cm³
3. C.738.46 cm³
4. D.1733.36 cm³.

Diffusion is slowest in solid particles than in particles of liquids and gases because

1. A.solid particles have more kinetic energy than the particles of liquids and gases
2. B.solid particles have less kinetic energy than the particles of liquids and gases
3. C.solid particles have less restrictions in their movement than liquid and gas particles
4. D.the particles in solids are far apart and the cohesive forces between them are negligible.

The experiment that showed that atoms have tiny positively charged nucleus was first carried out by

1. A.Moseley
2. B.Rutherford
3. C.Millikan
4. D.Dalton.

The atom of an element X is represented as ^Y_ZX. The basic chemical properties of X depend on the value of

1. A.Y
2. B.Z
3. C.Y − Z
4. D.Z − Y

The diagram above represents the electron sub-level for

1. A.carbon
2. B.nitrogen
3. C.oxygen
4. D.fluorine.

In the periodic table, electrical and thermal conductivities are properties of elements that

1. A.decrease across the period and increase down the group
2. B.increase across the period and decrease down the group
3. C.decrease across the period and down the group
4. D.increase across the period and down the group.

²³₁₁Na + ¹₀n → ²⁴₁₁Na
The reaction above is an example of

1. A.nuclear fission
2. B.nuclear fusion
3. C.artificial transmutation
4. D.beta decay.

Air boiled out of water as steam is richer in

1. A.nitrogen and oxygen
2. B.carbon (IV) oxide and oxygen
3. C.noble gases and carbon (IV) oxide
4. D.oxygen and noble gases.

In the course of purifying water for town supply, the water is passed through large settling tanks containing sodium aluminate (III) to remove

1. A.large particles
2. B.germs
3. C.fine particles
4. D.odour.

When a few drops of water is added to a blue anhydrous cobalt (II) chloride, the colour changes to

1. A.white
2. B.pink
3. C.red
4. D.blue.

117.0g of sodium chloride was dissolved in 1.0dm³ of distilled water at 25°C. Determine the solubility in mol dm⁻³ of sodium chloride at that temperature. [Na = 23, Cl = 35.5]

1. A.1.0
2. B.2.0
3. C.3.0
4. D.4.0

The uncovered raw food that is sold along major roads is likely to contain some amounts of

1. A.Pb
2. B.Cu
3. C.Ag
4. D.Na

What is the pH of a 0.001 mol dm⁻³ solution of sodium hydroxide?

1. A.14
2. B.13
3. C.12
4. D.11

The basicity of CH₃COOH is

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

0.05 mol dm⁻³ HCl is neutralized by 25cm³ NaOH. If the volume of acid used is 32.00cm³, what is the concentration of the base?

1. A.0.016 mol dm⁻³
2. B.0.032 mol dm⁻³
3. C.0.0… mol dm⁻³
4. D.0.064 mol dm⁻³.

Insoluble salts can be prepared by

1. A.titrating an alkali against an appropriate acid
2. B.reacting an acid with trioxocarbonate (IV) salt
3. C.direct combination of the elements which make up the salt.
4. D.mixing two soluble compounds containing the metallic radical and the acidic radical.

The oxidation state of carbon in HCOOH is

1. A.−1
2. B.+2
3. C.+3
4. D.0

What is the IUPAC nomenclature of the compound NaClO?

1. A.Sodium oxochlorate(I)
2. B.Sodium chloro(I) oxide
3. C.Sodium monooxochlorate(II)
4. D.sodium chloro(I) monoxide

In recharging a lead-acid accumulator, the reaction at the cathode can be represented as

1. A.Pb²⁺_(aq) + SO_4(aq)²⁻ → PbSO_4(s)
2. B.Pb²⁺_(aq) + 2e⁻ → Pb_(s)
3. C.Pb²⁺_(aq) + 2H₂O_(l) → PbO_2(s) + 4H⁺_(aq) + 4e⁻
4. D.Pb_(s) → Pb²⁺_(aq) + 2e⁻

If a given quantity of electricity liberates 0.65g of Zn²⁺, what amount of Hg²⁺ would be liberated by the same quantity of current? [Zn = 65, Hg = 201]

1. A.1.00g
2. B.2.01g
3. C.4.02 g
4. D.8.04 g

Which of the following reactions is endothermic?

1. A.C_(s) + O_2(g) → CO_2(g)
2. B.CaO_(s) + H₂O_(l) → Ca(OH)_2(s)
3. C.C_(s) + H₂O_(g) → CO_(g) + H_2(g)
4. D.HCl_(aq) + NaOH_(aq) → NaCl_(aq) + H₂O_(l)

A catalyst speeds up the rate of a chemical reaction by

1. A.taking part in the reaction
2. B.increasing the activation energy of the reaction
3. C.lowering the activation energy of the reaction
4. D.increasing the heat content.

The rate of a reaction usually decreases with a decrease in the concentration of reactants because

1. A.kinetic energy decreases
2. B.temperature increases
3. C.speed increases
4. D.reactants collision decreases.

N₂O_4(g) ⇌ 2NO_2(g)
In the reaction above, the equilibrium constant is

1. A.[NO₂]/[N₂O₄]
2. B.[2NO₂]/[N₂O₄]
3. C.[N₂O₄]/[NO₂]²
4. D.[NO₂]²/[N₂O₄]

The substance that is used in the steel industry for the removal of carbon, sulphur and phosphorus impurities from pig iron is

1. A.oxygen
2. B.chlorine
3. C.nitrogen
4. D.hydrogen

Which of the following compounds of trioxonitrate(V) will decompose to give dinitrogen(I) oxide and water when heated?

1. A.NaNO₃
2. B.Zn(NO₃)₂
3. C.Cu(NO₃)₂
4. D.NH₄NO₃

Use the diagram to answer questions 33 and 34.
The gas that can be used to demonstrate the experiment is

1. A.hydrogen chloride
2. B.hydrogen sulphide
3. C.nitrogen(II) oxide
4. D.dinitrogen(I) oxide.

Use the diagram to answer questions 33 and 34.
The colour of the fountain water is

1. A.blue
2. B.orange
3. C.red
4. D.yellow.

When a solution of ammonium trioxocarbonate(IV) is added to a solution of an unknown salt, a white precipitate which is soluble in dilute hydrochloric acid but insoluble in ethanoic acid is formed. This indicates the presence of

1. A.Ca²⁺
2. B.Na⁺
3. C.Zn²⁺
4. D.K⁺

Lead is used for making bullets and lead shots because of its

1. A.resistance to corrosion
2. B.low melting point
3. C.high density
4. D.flexibility.

The most common ores of iron include

1. A.haematite, malachite and limonite
2. B.chalcocite, calamine and bornite
3. C.magnetite, haematite and limonite
4. D.malachite, chalcocite and bornite

The type of isomerism shown by cis- and trans- isomers is

1. A.optical isomerism
2. B.positional isomerism
3. C.functional isomerism
4. D.geometrical isomerism.

If the silver mirror test is positive, it indicates the presence of an

1. A.alkyne
2. B.alkanol
3. C.alkanone
4. D.alkanal.

The IUPAC nomenclature for the structure above is

1. A.2, 3 − dichloro − 4, 4, 5 − trimethyl pent - 2- ene
2. B.4, 5 − dichloro − 2, 3 − dimethyl hex − 2 − ene
3. C.2, 3 − dichloro − 4, 4 − dimethyl hex − 2 − ene
4. D.2, 3 dichloro − 2, 2 − dimethyl hex − 2 − ene

If glucose is heated with concentrated tetraoxosulphate(VI) acid, it will be dehydrated to

1. A.carbon
2. B.carbon(IV) oxide
3. C.ethene
4. D.ethanol.

A hydrocarbon X with a molar mass of 26 consists of 92.3% carbon. What is its molecular formula?

1. A.C₂H₂
2. B.C₃H₃
3. C.C₄H₄
4. D.C₅H₅.

Reduction of nitroalkanes, nitrites and amides is a route for the preparation of

1. A.amines
2. B.alkenes
3. C.polymers
4. D.detergents

CH₃ − C(OH)(CH₃) − CH₂ − CH₃
The major product of the dehydration of the above compound is

1. A.CH₃ − C(=CH₂) − CH₂ − CH₃
2. B.CH₃ − CH(CH₃) − CH = CH₂
3. C.CH₃ − C(CH₃) = CH − CH₃
4. D.CH₃ − CH(CH₃) − CH₂ − CH₃

Reduction of alkanonoes with LiAlH₄ produces

1. A.primary alkanols
2. B.secondary alkanols
3. C.tertiary alkanols
4. D.polyhydric alkanols

The product obtained when a mixture of benzene vapour and hydrogen are passed over a nickel catalyst at 180°C is

1. A.cyclohexane
2. B.cyclopentane
3. C.n-hexane
4. D.n-pentane.

Polyvinyl chloride is used in the production of

1. A.glass
2. B.alloy
3. C.pipes
4. D.ceramics.

Detergents are manufactured with straight hydrocarbon chains so as to make them

1. A.soluble
2. B.biodegradable
3. C.cheaper
4. D.foamy.