JAMB Chemistry 2003 past questions and answers

What volume of oxygen is produced from the decomposition of 2 moles of KClO₃ at s.t.p? [Molar volume of a gas at s.t.p = 22.4 dm³]

1. A.22.4 dm³
2. B.33.6 dm³
3. C.44.8 dm³
4. D.67.2 dm³

Which of the following is a physical change?

1. A.Burning kerosine
2. B.Freezing ice-cream
3. C.Exposing white phosphorus to air
4. D.Dissolving calcium in water

What is the percentage by mass of oxygen in Al₂(SO₄)₃.2H₂O? [Al = 27, S = 32, H = 1, O = 16]

1. A.14.29%
2. B.25.39%
3. C.50.79%
4. D.59.25%

The filter in a cigarette reduces the nicotine content by

1. A.burning
2. B.adsorption
3. C.evaporation
4. D.absorption

3Cu + pHNO₃ → 3Cu(NO₃)₂ + 4H₂O + xNO
In the equation above, the values of p and x respectively are

1. A.1 and 3
2. B.2 and 3
3. C.6 and 2
4. D.8 and 2

Neutral atoms of neon with atomic number 10 have the same number of electrons as

1. A.O²⁺
2. B.Ca²⁺
3. C.K⁺
4. D.Mg²⁺

The noble gases owe their inactivity to

1. A.octet configuration
2. B.cyclic shape
3. C.hexagonal shape
4. D.obtuse configuration

According to the kinetic theory, an increase in temperature causes the kinetic energy of particles to

1. A.decrease
2. B.increase
3. C.remain constant
4. D.be zero

A gas exerts pressure on its container because

1. A.some of the its molecules are moving faster than others
2. B.of the collision of the molecules with each other
3. C.of the mass of the molecules of gas
4. D.the molecules of a gas collide with the walls of the container

When cathode rays are deflected onto the electrode of an electrometer, the instrument becomes

1. A.negatively charged
2. B.positively charged
3. C.neutral
4. D.bipolar

The weakest attractive force that can be observed between two molecules is

1. A.ionic
2. B.covalent
3. C.coordinate covalent
4. D.Van der Waals.

A consequence of global warming is

1. A.air pollution
2. B.water pollution
3. C.increased humidity
4. D.flooding

Which of the following ions is acidic?

1. A.K⁺
2. B.NO₃^-
3. C.S^2-
4. D.H₃O⁺

The structural component that makes detergent dissolve more quickly in water than soap is

1. A.–SO₃^-Na⁺
2. B.–COO^-Na⁺
3. C.–SO₄^-Na⁺
4. D.–COO^-K⁺

A liquid that will dissolve fat is

1. A.hydrochloric acid
2. B.calcium hydroxide
3. C.kerosine
4. D.water

What mass of K₂CrO₄ is required to prepare 250cm³ of 0.020 mol dm^-3 solution? [K₂CrO₄ = 194.2g mol^-1]

1. A.0.97 g
2. B.9.70 g
3. C.19.42 g
4. D.97.10 g

Farmlands affected by crude-oil spillage can be decontaminated by

1. A.adding acidic solutions
2. B.using aerobic bacteria
3. C.pouring water on the affected area
4. D.burning off the oil from the area.

When 10g of sodium hydroxide is dissolved in 1000cm³ of water, the solution formed is approximately [Na = 23, H = 1, O = 16]

1. A.0.01 mol dm^-3
2. B.0.10 mol dm^-3
3. C.0.25 mol dm^-3
4. D.0.50 mol dm^-3

A change in the temperature of a saturated solution disturbs the equilibrium between the

1. A.dissolved solute and the solvent
2. B.solvent and the undissolved solute
3. C.dissolved solute and the undissolved solute
4. D.dissolved solute and the solution.

If an equilibrium reaction has ΔH > 0, the reaction will proceed favourably in the forward direction at

1. A.high temperature
2. B.any temperature
3. C.low temperature
4. D.minimum temperature.

2HCl_(aq) + CaCO_3(s) → CaCl_2(s) + CO_2(g) + H₂O_(l)
From the reaction above, which of the curves in the diagram represents the production of carbon (IV) oxide as dilute HCl is added?

1. A.L
2. B.M
3. C.N
4. D.P

The commonest feature of reactions at the anode is that

1. A.electrons are consumed
2. B.oxidation is involved
3. C.ions are reduced
4. D.electrode dissolves.

Which of the following will change when a catalyst is added to a chemical reaction?

1. A.The activation energy
2. B.The potential energy of the reactants.
3. C.The heat of reaction
4. D.The potential energy of the products.

If Y is an oxidizing agent that reacts with a reducing agent, Z, which of the following is correct?

1. A.Y increases in oxidation number
2. B.Y becomes reduced
3. C.Z loses protons
4. D.Z gains protons

When at equilibrium, which of the reactions below will shift to the right if the pressure is increased and the temperature is kept constant?

1. A.2SO_3(g) ⇌ 2SO_2(g) + O_2(g)
2. B.2CO_2(g) ⇌ 2CO_(g) + O_2(g)
3. C.2H_2(g) + O_2(g) ⇌ 2H₂O_(g)
4. D.2NO_(g) ⇌ N_2(g) + O_2(g)

In the electrolysis of a concentrated solution of sodium chloride using inert electrodes, which of the following ions are discharged at the cathode and anode respectively?

1. A.Na⁺ and Cl^-
2. B.Na⁺ and OH^-
3. C.H⁺ and OH^-
4. D.H⁺ and Cl^-

CO_(g) + H₂O_(g) → CO_2(g) + H_2(g)
From the reaction above, calculate the standard heat change if the standard enthalpies of formation of CO_2(g), H₂O_(g) and CO_(g) in kJ mol^-1 are –394, –242 and –110 respectively.

1. A.–262 kJ mol^-1
2. B.–42 kJ mol^-1
3. C.+42 kJ mol^-1
4. D.+262 kJ mol^-1

When sugar is dissolved in tea, the reaction is always accompanied by

1. A.positive entropy change
2. B.negative entropy change
3. C.no entropy change
4. D.a minimum entropy change.

Which of the following is an electrolyte?

1. A.Alcohol
2. B.Sodium acetate solution
3. C.Solid potassium hydroxide
4. D.Mercury

Metals of the first transition series have special properties which are different from those of groups I and II elements because they have partially filled

1. A.s orbitals
2. B.p orbitals
3. C.d orbitals
4. D.f orbitals

Hydrogen can be displaced from a hot alkaline solution by

1. A.Fe
2. B.Cu
3. C.Ca
4. D.Sn

Which of the following statements is true of sulphur (IV) oxide?

1. A.It forms tetraoxosulphate (VI) acid with water
2. B.It is an odourless gas
3. C.It is an acid anhydride
4. D.It forms white precipitate with acidified barium chloride.

The salt that will form a precipitate soluble in excess ammonia solution is

1. A.Ca(NO₃)₂
2. B.Cu(NO₃)₂
3. C.Mg(NO₃)₂
4. D.Al(NO₃)₃

The metal that liberates hydrogen from cold water in bubbles only is

1. A.Na
2. B.K
3. C.Ca
4. D.Al

Chlorine gas turns a damp starch-iodide paper

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

The modern process of manufacturing steel from iron is by

1. A.treatment with acids
2. B.oxidation
3. C.blast reduction
4. D.treatment with alkalis.

In the diagram above, Y is

1. A.NO
2. B.NO₂
3. C.N₂O₅
4. D.N₂O₄

Ethene reacts with hydrogen bromide to give

1. A.CH₂Br₂
2. B.CH₃CH₂Br
3. C.C₂H₂Br₂
4. D.CHBr₃

Carbohydrates are compounds containing carbon, hydrogen and oxygen in the ratio

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

How many isomers does pentane have?

1. A.6
2. B.5
3. C.4
4. D.3

The leachate of a certain plant ash is used in local soap-making because it contains.

1. A.sodium chloride and potassium hydroxide
2. B.sodium hydroxide
3. C.potassium hydroxide
4. D.soluble carbonates and hydrogen carbonates.

The formula for ethyl butanoate is

1. A.C₃H₇COOC₂H₅
2. B.C₂H₅COOC₃H₇
3. C.C₄H₉COOC₂H₅
4. D.C₂H₅COOC₄H₉

The type of reaction that is peculiar to benzene is

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

Ethanol reacts with excess acidified K₂Cr₂O₇ to produce

1. A.ethanedioic acid
2. B.ethanal
3. C.ethyl ethanoate
4. D.ethanoic acid.

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. [H = 1, C = 12, O = 16]

1. A.CH₂O
2. B.C₃H₆O₃
3. C.C₆H₁₂O₆
4. D.C₆H₆O₃

The process by which atoms are rearranged into different molecular structures in the petroleum refining process is referred to as

1. A.catalytic cracking
2. B.hydrocracking
3. C.polymerization
4. D.reforming.

Which of the following is found in cotton.

1. A.Starch
2. B.Cellulose
3. C.Fat
4. D.Oil

The principal constituent of natural gas is

1. A.methane
2. B.ethane
3. C.propane
4. D.butane