NECO SSCE - Chemistry - 2003 (Objective)

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Question 9 Report

Which element is the most electronegative?

calcium

fluorine

iodine

oxygen

sodium

Answer Details

Read lesson note on Atomic Structure And Bonding (JAMB)

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Question 10 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+]

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 11 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.

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 12 Report

What change will occur to the equilibrium mixture
\( 2CrO^{2-}_4(aq) + 2H^+(aq) ⇔ Cr_2O^{2-}_7(aq) + H_2O(l) \) when excess sodium hydrogen solution is added?

A yellow precipitate of Cr(OH)₃ is formed

An orange precipitate of Cr(OH)₃ is formed

The colour changes from orange to yellow

The colour changes from yellow to orange

There is no visible reaction.

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Read lesson note on Chemical Kinetics And Equilibrium Systems (Ghana Only) (WAEC)

Read lesson note on Structure Of The Atom (WAEC)

Chemical Kinetics And Equilibrium Systems (Ghana Only)

Structure Of The Atom

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Question 13 Report

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

2-chloro -3 methylbut -2yne

2 -chloro -3 methylbut -2ene

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 14 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

C₄H₉Br

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Read lesson note on Organic Compounds (JAMB)

Organic Compounds

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Question 15 Report

Which metal is extracted from bauxite?

aluminium

calcium

copper

magnesium

tin

Answer Details

Read lesson note on Metals And Their Compounds (JAMB)

Metals And Their Compounds

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Question 16 Report

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

acquire certain colours

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 17 Report

Which method is used for the purification of copper from its ore?

distillation

electrochemical

electrolysis

neutralization

reduction

Answer Details

Read lesson note on Electrolysis (JAMB)

Electrolysis

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Question 18 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

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 19 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?

\( \text{0} \)

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Read lesson note on Atomic Structure And Bonding (JAMB)

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Question 20 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

92 protons and 238 neutrons

Answer Details

Read lesson note on Atomic Structure And Bonding (JAMB)

Read lesson note on Chemical Equilibria (JAMB)

Chemical Equilibria

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Question 21 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)

Answer Details

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

Acids, Bases And Salts

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Question 22 Report

What mass of copper is deposited when 6.5g of granulated zinc reacts with excess copper(II) tetraoxosulphate(VI) solution?

The equation for the reaction is: Zn(s) + \( CuSO_4(aq)→ ZnSO_4(aq)+ Cu(s)\)[CU= 64; Zn=65]

3.2 g

3.25 g

6.4 g

6.5 g

64.0 g

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Read lesson note on Stoichiometry And Chemical Reactions (WAEC)

Stoichiometry And Chemical Reactions

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Question 23 Report

A calcium atom and a calcium ion have the same

chemical properties

electric charge

electronic structure

number of electrons

number of neutrons

Answer Details

Read lesson note on Atomic Structure And Bonding (JAMB)

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Question 24 Report

The number of hydrogen ions in 1.0dm6.00x10³ of a 0.25 mole dm6.00x10^-3 tetraoxosulphate(Vl) acid solution is
[Avogadro constant = 6.0 x 1 0]

1.45x10²³

1.50 x l0²³

3.00x10²³

3.15x10²³

6.00x10²³

Answer Details

Read lesson note on Stoichiometry And Chemical Reactions (WAEC)

Stoichiometry And Chemical Reactions

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Question 25 Report

Which metal is a constituent of both bronze and solder?

copper

lead

silver

tin

zinc

Answer Details

Read lesson note on Metals And Their Compounds (JAMB)

Metals And Their Compounds

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Question 26 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]

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

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

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

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

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

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

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Question 27 Report

Which metal bromide is widely used in photography?

calcium bromide

magnesium bromide

potassium bromide

silver bromide

sodium bromide

Answer Details

Read lesson note on Metals And Their Compounds (JAMB)

Metals And Their Compounds

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Question 28 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.

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)

Separation Of Mixtures And Purification Of Chemical Substances

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Question 29 Report

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

Chlorine will be given off at the cathode

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

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 30 Report

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

a bleaching

a dehydrating

an oxidizing

a precipitating

a reducing

Answer Details

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 31 Report

What is formed when starch is completely hydrolysed?

fructose

glucose

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 32 Report

Which is NOT a synthetic polymer?

nylon

Orion

Perspex

polystyrene

wool

Answer Details

Read lesson note on Basic Biochemistry And Synthetic Polymers (WAEC)

Basic Biochemistry And Synthetic Polymers

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Question 33 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

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 34 Report

Which separation technique is routinely applied in the petroleum industry?

chromatography

distillation

evaporation

fractional crystallization

fractional distillation

Answer Details

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 35 Report

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

CH₃CH₂CHO

CH₃CH₂CH2OH

CH₃CH₂COQH

CH₃CH₂0CH

CH₃CH₃OH

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Question 36 Report

The reaction C₂H₆ → C₂H + H₂ is known as

dehydration

dehydrogenation

displacement

hydrogenation

reduction

Answer Details

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