JAMB UTME - Chemistry - 1979

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Question 12 Report

In which of the following reactions is sulphur dioxide acting as an oxidizing agent?

SO ₂ + 2HNO₃ →H₂SO₄ + NO₂ + Heat

2SO₂ + 2H₂O + O₂→ 2H₂SO₄

SO₂ + 2H₂O + CI₂→ H₂SO₄ + 2HCI

SO₂ + 2H₂S → 3S + 2H₂O Correct answer

SO₂ + H₂O → H₂SO₃

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Read lesson note on Oxidation And Reduction (JAMB)

Oxidation And Reduction

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Question 13 Report

The reaction of zinc with copper (ll) ions in aqueous solution can be represented as follows: Cu ²⁺(aq) +Zn (s) → Cu(s) + Zn ²⁺(aq).Which of the following is the most complete description of this reaction?

Cpper (ll) ions are being reduced

Zinc is being oxidized.

Copper (ll) ions and zinc are being reduced

copper (ll) ions and zinc are being oxidized

copper(ll) ions are being reduced and zinc oxidized Correct answer

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Read lesson note on Oxidation And Reduction (JAMB)

Oxidation And Reduction

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Question 14 Report

0.1 Faraday of electricity was passed through a solution of copper (ll) sulphate. The maximum weight of copper deposited on the cathode would be [Cu = 64]

64.0g

32.0g

16.0g

6.4 g

3.2g Correct answer

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Read lesson note on Electrolysis (JAMB)

Electrolysis

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Question 15 Report

Which are the correct IUPAC names for H-CO₂CH₃ and CH = CH

Methyl methanoate and ethene

Metanoic acid and ethyne

Ethyl methanoate and ethyne

Methyl methanoate and ethyne Correct answer

Ethanoic acid and ethene

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Read lesson note on Chemistry Of Carbon Compounds (Nigeria Only) (WAEC)

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Question 16 Report

The reaction 3C(s) + 2Fe₂O₃(s) = 4Fe(s) + 3CO₂(g): \(\Delta\)H =46.0 kJ is

isothermic

adiabatic

isobaric

endothermic Correct answer

exothermic

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Read lesson note on Energy Changes (JAMB)

Read lesson note on Energy And Energy Changes (WAEC)

Energy Changes

Energy And Energy Changes

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Question 17 Report

One of the following techniques can be used to show that chlorophyll pigment is a mixture of chemical compounds and not a single coloured compound

cystallization

hydrolysis

sublimation

filtration

chromatography Correct answer

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Read lesson note on Separation Of Mixtures And Purification Of Chemical Substances (JAMB)

Separation Of Mixtures And Purification Of Chemical Substances

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Question 18 Report

Which of the following statements is true?

an increase in the temperature of a given mass of gas increases the number of gas molecules

an increase in the temperature of the gas does not affect the kinetic energy

an increase in the pressure of the gas is proportional to the increase in volume

a increase in the pressure of a gas is proportional to the decrease in volume at constant temperature Correct answer

a decrease in the pressure of the gas decreases the number of gas molecules present

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Read lesson note on Kinetic Theory Of Matter And Gas Laws (JAMB)

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Question 19 Report

When a piece of charcoal enclosed in a cylinder containing air is ignited

the toatl volume of air is increased

the relative amount of oxygen present is increased

the relative amount of nitrogen present is decreased

the relative amount of carbondioxide present is increased Correct answer

the ratio of oxygen to nitrogen in the system is increased

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Read lesson note on Kinetic Theory Of Matter And Gas Laws (JAMB)

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Question 20 Report

A piece of metal (M) is dissolved in nitric acid and the resulting solution is treated with a small quantity of sodium hydroxide to produce a white precipitate (B) which redissolves on the addition of excess alkali. The precipitate (B)when ignited in a crucible produces the oxide of the metal(m). The METAL M is

Zn Correct answer

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Read lesson note on Chemical Combination (JAMB)

Chemical Combination

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Question 21 Report

\(50cm^{3}\) of hydrogen are sparked with \(20cm^{3}\) of oxygen at \(100°C\) and \(1atm\) . The total volume of the residual gases in

50 cm³ Correct answer

10 cm³

40 cm³

30 cm³

70 cm³

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Read lesson note on Kinetic Theory Of Matter And Gas Laws (JAMB)

Read lesson note on Stoichiometry And Chemical Reactions (WAEC)

Stoichiometry And Chemical Reactions

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Question 22 Report

The reaction between hydrogen and iodine may be represented by the equation H₂(g)+ I₂(g) → 2HI(g), and is exothermic. Therefore

an increase in temperature favours the forword reaction

an increase in pressure favours the backward reaction

both pressure and temperature muct be increased to favour the forward reaction

a decrease in temperature will favour the forward reaction Correct answer

a decrease in pressure and an increase in temperature will favour the forward reaction

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Read lesson note on Energy Changes (JAMB)

Energy Changes

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Question 23 Report

Hydrogenation may be effected by

the removal of hydrogen from an alkane in the presence of a catalyst

the addition of hydrogen to an alkane in the presence of a catalyst

the addition of hydrogen to an alkyne Correct answer

the removal of hydrogen from an alkyne

the addition of hydrogen to an ethyl alcohol

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Read lesson note on Chemistry Of Carbon Compounds (Nigeria Only) (WAEC)

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Question 24 Report

When ammonium, potassium and calcium carbonates are each separately heated

none of them will decompose

each of them will decompose to give carbondioxide and the respective oxide

ammonium carbonate and potassium carbonate will not decompose

only ammonium carbonate and the respective oxide Correct answer

ammonium carbonate will decompose to give carbondioxide, water and ammonia

Answer Details

Read lesson note on Acids, Bases And Salts (JAMB)

Acids, Bases And Salts

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Question 25 Report

Which one of these compounds will NOT give an oxygen gas on heating?

Manganese dioxide

Hydrogen peroxide

Zinc nitrate Correct answer

Sodium nitrate

Ammonium nitrate

Answer Details

Read lesson note on Oxidation And Reduction (JAMB)

Read lesson note on Acids, Bases And Salts (Ghana Only) (WAEC)

Oxidation And Reduction

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Question 26 Report

A gas occupies 30.0 dm³ at S.T.P. What volume would it occupy at 91^oC and 380 mm Hg?

20. 0dm³

40.0dm³

60. 0dm³

80. 0dm³ Correct answer

100. 0dm³

Answer Details

Read lesson note on Kinetic Theory Of Matter And Gas Laws (JAMB)

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Question 27 Report

In the redox reaction 2Fe²⁺ + CI₂ → 2Fe ^{3 +} + 2Cl

Cl₂ is reduced because it has lost electrons

Cl₂ is reduced because its oxidation number has decreased Correct answer

Cl₂ is reduced because its molecule is change to two ions

Fe²⁺ is reduced because it has lost electrons

Fe²⁺ is reduced because it has gained electrons

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Read lesson note on Redox Reactions (WAEC)

Redox Reactions

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Question 28 Report

12 g of solid protassium chlorate (KCIO) were added to 40 g of water and heated to dissolve all the solid. As the solution cools, crystals of potassium chlorate at 66 ^oC. The solubility of potassium chlorate at 66 ^oC is therefore

30 Correct answer

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Read lesson note on Solubility (JAMB)

Solubility

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Question 29 Report

Two metallic ions associated with hard water are

copper and zinc

magnesium and silver

calcium and magnesium Correct answer

potassium and tin

sodium and lead

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Read lesson note on Metals And Their Compounds (JAMB)

Metals And Their Compounds

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Question 30 Report

Methanoic acid mixes with water in all proportions and has about the same boiling point as water which of the following methods would you adopt to obtain pure water from a mixture of stand, water and methanoic acid?

fractional distillation

filtration followed by distillation

neutralization with sodium hydroxide followed by distillation

esterification with ethanol followed by distillation

neutralization with sodium hydroxide followed by filtration Correct answer

Answer Details

Read lesson note on Acids, Bases And Salts (Ghana Only) (WAEC)

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Question 31 Report

Indicate which of the following statements is not true as we move from left to right along the periodic Table:

atomic number of elements increases

atomic mass of elements increases

electropositive character of elements increases Correct answer

electronegative character of elements increases

number of electrons in the outermost orbits of element increases

Answer Details

Read lesson note on Periodic Chemistry (Nigeria Only) (WAEC)

Periodic Chemistry (Nigeria Only)

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Question 32 Report

Helium atoms are chemically unreactive because

there are no electrons around the nucleus

the number of protons equals the number of electrons

there are equal number of protons and neutrons in the nucleus

the outer electron shell is completely filled Correct answer

the atoms contain only protons

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Read lesson note on Atomic Structure And Bonding (JAMB)

Atomic Structure And Bonding

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Question 33 Report

Bronze is an alloy of

copper, zinc and nickel

aluminium and copper

copper and zinc

tin and zinc

tin and copper Correct answer

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Read lesson note on Metals And Their Compounds (JAMB)

Metals And Their Compounds

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Question 34 Report

Phosphorus burns in oxygen according to the equation P₄ + 50₂ → P₄O₁₀. How many litres of oxygen will be required at S.T.P for complete oxidation of 12.4g of phosphorus? [P = 31,O = 16 and molar volume of a gas at S.T.P = 22.4 litres]

5. 20

11. 20 Correct answer

2. 24

20. 20

6. 20

Answer Details

Read lesson note on Stoichiometry And Chemical Reactions (WAEC)

Stoichiometry And Chemical Reactions

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Question 35 Report

Consider the following exothermic reaction 2SO₂(g) + O₂(g) = 2SO₃ (g) . If the temperature of the reaction is reduced from 800_oC to 500_oC, and no other change takes place, then

the reaction rate increases

concentration of SO₃ decreases

concentration of SO₃ increases Correct answer

SO₂ gas becomes unreactive

O₂ gas becomes unreactive

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Read lesson note on Kinetic Theory Of Matter And Gas Laws (JAMB)

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Question 36 Report

Which of the structural formal above is ethanoic acid is

E Correct answer

Answer Details

Read lesson note on Acids, Bases And Salts (JAMB)

Acids, Bases And Salts

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Question 37 Report

Starch can be converted to ethyl alcohol by

distillation

fermentation Correct answer

isomerization

cracking

cooking

Answer Details

Read lesson note on Electrolysis (JAMB)

Electrolysis

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Question 38 Report

Which of the following statements is true? When the potassium atom forms its ion

it gains one electron and becomes neutral

its atomic number decreases

it achieves electronic configuration of orgon Correct answer

it loses one proton

it loses one neutron

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Question 39 Report

When excess ethanol is heated to 145 ^oC in the presence of concentrated sulphuric acid, the product is

diethyl ether Correct answer

ethyne

diethyl sulphate

acetone

ethanoic acid

Answer Details

Read lesson note on Chemistry Of Carbon Compounds (Nigeria Only) (WAEC)

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Question 40 Report

The solution of a sample in a tube will be identified as a chloride if it gives

a white precipitate on addition of AgNO₃ and barium chloride solutions

a white precipiate when acidified with HCI, and then AgNO₃ solution added

a white precipitate when acidified with dilute HNO₃ and then AgNO₃ solution added Correct answer

a white precipitate when acidified with dilute H₂SO₄ and then barium nitrate solution added

a pungent smell of chlorine gas when dilute HCI and MnO₂ are added

Answer Details

The solution of a sample in a tube will be identified as a chloride if it gives a white precipitate when acidified with dilute HNO3 and then AgNO3 solution is added. This is because the test is a confirmatory test for chloride ions, and the white precipitate formed is silver chloride (AgCl). Chloride ions react with silver nitrate (AgNO3) to form a white precipitate of AgCl, which is insoluble in water and dilute nitric acid.

Read lesson note on Periodic Chemistry (Ghana Only) (WAEC)

Periodic Chemistry (Ghana Only)

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Question 41 Report

Which of the following statements applies during the electroysis of sodium hydroxide sodium hydroxide solution using platinum electrodes?

Na⁺ ions are discharged at the cathode

Hydrogen ions are discharged at the anode

the concentration of sodium hydroxide decrease at both electrode compartments

the concentration of sodium hydroxide increases at the cathode only Correct answer

the concentration of sodium hydroxide increases at the anode only

Answer Details

Read lesson note on Electrolysis (JAMB)

Read lesson note on Acids, Bases And Salts (Ghana Only) (WAEC)

Electrolysis

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Question 42 Report

In the extraction of aluminum from purified bauxite by electrolysis, cryolite is used because

it makes bauxite a better conductor of electricity

it makes bauxite melt at a lower temperature Correct answer

it makes aluminium purer

it prevents aluminium from getting oxidized

it protects the carbon electrodes used in the process

Answer Details

Read lesson note on Electrolysis (JAMB)

Electrolysis

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Question 43 Report

The IUPAC name for

2-methylbut-3-ene

2-methylbut-4-ene

3-methylbut-2-ene

3-methylbut-1-ene Correct answer

3-methylpent-1-ene

Answer Details

Read lesson note on Chemistry Of Carbon Compounds (Nigeria Only) (WAEC)

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Question 44 Report

How many grams of HBr would exactly be required to react with 2 g of propyne? (C =12, H=1, Br = 80)

4. 1 g

6. 1 g

8. 1g Correct answer

16.2g

Answer Details

Read lesson note on Kinetic Theory Of Matter And Gas Laws (JAMB)

Read lesson note on Stoichiometry And Chemical Reactions (WAEC)

Stoichiometry And Chemical Reactions

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Question 45 Report

Weighed salts Y and Z were left exposed in the laboratory overnight. In the morning Y had gained weight, and Z had become liquid. What conclusion could be drawn about the nature of the two salts?

Z is efflorescent

Y and Z are efflorescent

Y and Z are deliquescent Correct answer

Y and Z are hygroscopic

Y is deliquescent

Answer Details

Read lesson note on Acids, Bases And Salts (Ghana Only) (WAEC)

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Question 46 Report

the vapour density of a gas may be defined as

the mass of a unit volume of the gas compared to an equal volume of water vapour

the mass of a unit volume of the gas compared to an equal volume of hydrogen Correct answer

the mass of a unit volume of the gas compared to an equal volume of oxygen

the mass of a unit volume of the gas minus the vapour pressure of water

two times the relative molecular mass of the gas

Answer Details

Read lesson note on Kinetic Theory Of Matter And Gas Laws (JAMB)