NECO SSCE - Chemistry - 2003 (Objective)

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Question 6 Report

Which statement is NOT true about the composition of starch?

It contains only the atoms of carbon, hydrogen oxygen

It is a polysaccharide

Its empirical formula is C₂H₂0. Correct answer

It is made from the monomerC₆H₁₂O₆.

The hydrogen and oxygen atoms are in the ratio 2:1.

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

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Question 7 Report

Which compound will give propane when it Is dehy drated by an excess of hot, concentrated tetraoxosvlphate(VI) acid?

CH₃CH₂CHO

CH₃CH₂CH2OH Correct answer

CH₃CH₂COQH

CH₃CH₂0CH

CH₃CH₃OH

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Question 8 Report

A calcium atom and a calcium ion have the same

chemical properties

electric charge

electronic structure

number of electrons

number of neutrons Correct answer

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Read lesson note on Atomic Structure And Bonding (JAMB)

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Question 9 Report

Which metal is extracted from bauxite?

aluminium Correct answer

calcium

copper

magnesium

tin

Answer Details

Read lesson note on Metals And Their Compounds (JAMB)

Metals And Their Compounds

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Question 10 Report

What is formed when starch is completely hydrolysed?

fructose

glucose Correct answer

lactose

maltose

sucrose

Answer Details

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

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 11 Report

Why is tetraoxosulphate(VI) acid NOT used for making carbon dioxide from calcium carbonate? It is

a dehydrating agent

a strong acid

an oxidising agent

dibasic

forms insoluble calcium tetraoxosulphate(Vl) Correct answer

Answer Details

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

Acids, Bases And Salts

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Question 12 Report

An organic compound gave the following results on analysis: C = 29.3% ; H = 5.7%; Br = 65%.
What is the empirical formula of the compound? [C = 12, H = 1, Br=80]

CH₃Br

C₂H₅Br

C₃H₅Br

C₃H₇Br Correct answer

C₄H₉Br

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Read lesson note on Organic Compounds (JAMB)

Organic Compounds

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Question 13 Report

Which metal is a constituent of both bronze and solder?

copper

lead

silver

tin Correct answer

zinc

Answer Details

Read lesson note on Metals And Their Compounds (JAMB)

Metals And Their Compounds

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Question 14 Report

In the reaction 2H₂S(g) + SO₂(g) → 2H₂SO(I)+3S(s)SO₂is acting as _agent

a bleaching

a dehydrating

an oxidizing Correct answer

a precipitating

a reducing

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

Read lesson note on Oxidation And Reduction (JAMB)

Oxidation And Reduction

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Question 15 Report

Which separation technique is routinely applied in the petroleum industry?

chromatography

distillation

evaporation

fractional crystallization

fractional distillation 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 16 Report

The pH of water is 7.

What is the pH of orange juice?

above 10

below 2

between 5.5 and 6.5 Correct answer

between 7.5 and 8.5

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

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Question 17 Report

The reaction C₂H₆ → C₂H + H₂ is known as

dehydration

dehydrogenation Correct answer

displacement

hydrogenation

reduction

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

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Question 18 Report

What change will occur during the electrolysis of brine using carbon electrodes?

Chlorine will be given off at the cathode Correct answer

Oxygen gas will be given off at the anode

Sodium will be deposited at the cathode

The resulting solution, after electrolysis, will be acidic.

The volumes of hydrogen and chlorine given off during the same time are equal

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Read lesson note on Electrolysis (JAMB)

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

Electrolysis

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Question 19 Report

Small amounts of compounds of transition metals are sometimes added to glass during manufacture in order to make the glass

acquire certain colours Correct answer

easier to melt

easier to mould

little brittle

more transparent

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Read lesson note on Chemical Combination (JAMB)

Chemical Combination

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Question 20 Report

Which element is the most electronegative?

calcium

fluorine Correct answer

iodine

oxygen

sodium

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Read lesson note on Atomic Structure And Bonding (JAMB)

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Question 21 Report

What is the concentration (in mol dm³) of a solution containing 28 g of potassium hydroxide per 100 cm³ of solution? (K=39; H=1; 0=16)

0.01

0.05 Correct answer

0.1

0.5

2.8

Answer Details

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

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

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Question 22 Report

What is the IUPAC name of CH₃CCI=C(CH₃)2?

2-chloro -3 methylbut -2yne

2 -chloro -3 methylbut -2ene Correct answer

2 -chloro -3 methylbutene

3- methyl -2-chlorobut -2-ene

3- methyl -2. chlorobut -2 yne

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

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Question 23 Report

Naturally occurring lithium consists of 90% \( ^7_3Li \text{ and 10% } ^6_3 Li. \) What is the relative atomic mass of lithium?

6.8

6.9 Correct answer

7.1

Answer Details

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

Read lesson note on Atomic Structure And Bonding (JAMB)

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Question 24 Report

Why does the treatment of cotton fabrics with dilute acids weaken the materials?

Cotton is hydrolysed completely to glucose

The fabrics are soluble in dilute acids

The molecular chains are partially broken Correct answer

The molecular chain length f the fabric increases

The thread holding the fabric together Is completely destroyed.

Answer Details

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

Read lesson note on Oxidation And Reduction (JAMB)

Acids, Bases And Salts

Oxidation And Reduction

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Question 25 Report

How many Faradays of electricity are required to liberate 9g of aluminium? [Al = 27]

0.1

0.3

1 Correct answer

2.7

Answer Details

Read lesson note on Electrolysis (JAMB)

Electrolysis

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Question 26 Report

Which metal bromide is widely used in photography?

calcium bromide

magnesium bromide

potassium bromide

silver bromide Correct answer

sodium bromide

Answer Details

Read lesson note on Metals And Their Compounds (JAMB)

Metals And Their Compounds

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Question 27 Report

An atom of element X has an electronic configuration of \( 1s^22p^33s^23p^2. \) In which group of the periodic table is X?

\( \text{0} \)

4 Correct answer

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Read lesson note on Atomic Structure And Bonding (JAMB)

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Question 28 Report

What is the change in the oxidation number of phosphorus in the following reaction?

4P(s) + 5O₂(ag) → 2P₂O₅(s)

0 to 2

0 to 5 Correct answer

4 to 2

4 to 5

4 to 10

Answer Details

Read lesson note on Oxidation And Reduction (JAMB)

Oxidation And Reduction

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Question 29 Report

At s.t.p, a mole of chlorine occupies 22.4dm³. If the temperature is changed to 35°C and the pressure to 750mHg the of the new volume will be [Cl = 35.5]

\( ^{\text{760 x 22.4 x 308}} \text{750 x 273x 35.5} dm^3 \)

\( ^{\text{760 x 22.4 x 308}} \text{750 x 273}^x dm^3 \) Correct answer

\( ^{\text{750 x 22.4 x 35.5}} \text{760 x 273dm3} \)

\( ^{\text{760 x 22.4 x 35.5}} \text{750x22.3x273} \)

\( ^{\text{760 x 22.4 x 35.5}} \text{750 x 308dm3} \)

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

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Question 30 Report

Which formula is used to indicate the degree of acidity of an acid?

\( [H^+] = ^{\text{mass of acid relative}} molecular mass of acid \)

F = number of H+ = ions x molar mass of the acid

Kw = [H+][OH-]

pH = - log₁₀[H+] Correct answer

pKa = -log₁₀Ka

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

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

Periodic Chemistry (Ghana Only)

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Question 31 Report

B is an isotope of the element \(^{238} _{92}Ur\). The isotope B has

46 protons and 119 neutrons

92 protons and 92 neutrons

92 protons and 146 neutrons Correct answer

92 protons and 238 neutrons

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Read lesson note on Atomic Structure And Bonding (JAMB)

Read lesson note on Chemical Equilibria (JAMB)

Chemical Equilibria

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Question 32 Report

Chlorine displaces bromine from aqueous potassium bromide because

bromine is a liquid at room temperature

bromine is weakly acidic.

bromine has a greater atomic radius than chlorine

chlorine is a stronger oxidising agent than bromine. Correct answer

the density of chlorine is less than the density of bromine.

Answer Details

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

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