NECO SSCE - Chemistry - 2003 (Objective)

What is the number of moles of NaHCO₃in 250cm³ of its solution if the solution contains 8.4 g of NaHCO₃ in 1 dm³ of the solution. [Na = 23, 0 = 16, C = 12, H = 1)

0.25

0.05

0.025 Correct answer

0.01

Answer Details

Read lesson note on Stoichiometry And Chemical Reactions (WAEC)

Stoichiometry And Chemical Reactions

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Question 10 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)

Atomic Structure And Bonding

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Question 11 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 12 Report

The reaction C₂H₆ → C₂H + H₂ is known as

dehydration

dehydrogenation Correct answer

displacement

hydrogenation

reduction

Answer Details

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

Chemistry Of Carbon Compounds (Nigeria Only)

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Question 13 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)

Kinetic Theory Of Matter And Gas Laws

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Question 14 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

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Oxidation And Reduction

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Question 15 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)

Kinetic Theory Of Matter And Gas Laws

Acids, Bases And Salts (Ghana Only)

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Question 16 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 Correct answer

3.00x10²³

3.15x10²³

6.00x10²³

Answer Details

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Stoichiometry And Chemical Reactions

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Question 17 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

Answer Details

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

Electrolysis

Acids, Bases And Salts (Ghana Only)

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Question 18 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

Answer Details

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

Acids, Bases And Salts (Ghana Only)

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Question 19 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.

Answer Details

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

Chemistry Of Carbon Compounds (Nigeria Only)

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Question 20 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

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Acids, Bases And Salts

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Question 21 Report

Ethene decolourises acidified potassium tetraoxomanganate(VII) solution. Which gas will decolourise bromine water?

CH₄

C₂H₆

C₃H₆ Correct answer

C₃H₈

C₆H₆

Answer Details

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Chemistry Of Carbon Compounds (Ghana Only)

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Question 22 Report

Which is NOT a synthetic polymer?

nylon

Orion

Perspex

polystyrene

wool Correct answer

Answer Details

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Basic Biochemistry And Synthetic Polymers

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Question 23 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

Answer Details

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Organic Compounds

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Question 24 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 Correct answer

6.5 g

64.0 g

Answer Details

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Stoichiometry And Chemical Reactions

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Question 25 Report

Chlorine is used in water purification because it

bleaches impurities in the water

decolorizes water

destroys bacteria Correct answer

is extremely soluble in water

is pleasant tasting

Answer Details

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Water

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Question 26 Report

What mass of silver is deposited when a current of 2.6 A is passed through a solution of a silver salt for 40 minutes? [Ag= 108 ; F=96500C]

6.89g

6.93g

6.98g Correct answer

7.04g

7.12g

Answer Details

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Chemical Kinetics And Equilibrium System (Nigeria Only)

Electrolysis

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Question 27 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

Answer Details

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

Read lesson note on Oxidation And Reduction (JAMB)

Kinetic Theory Of Matter And Gas Laws

Oxidation And Reduction

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Question 28 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 29 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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Chemical Combination

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Question 30 Report

The boiling point of water is higher than the boiling point of ethanol because

the bonding in water is electrovalent (ionic) whereas the bonding in ethanol is convalent

the hydrogen bonding between water molecules is stronger than the hydrogen bonding between ethanol molecules Correct answer

water has a higher lattice energy than ethanol.

water has hydrogen bonding between its molecules but ethanol has no hydrogen bonging between its molecules;

water is a better solvent than ethanol.

Answer Details

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Chemical Bonds (Nigeria Only)

Energy And Energy Changes

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Question 31 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

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Kinetic Theory Of Matter And Gas Laws

Separation Of Mixtures And Purification Of Chemical Substances

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Question 32 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

Answer Details

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Question 33 Report

Which separation technique is routinely applied in the petroleum industry?

chromatography

distillation

evaporation

fractional crystallization

fractional distillation Correct answer

Answer Details

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Separation Of Mixtures And Purification Of Chemical Substances

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Question 34 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

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Acids, Bases And Salts

Oxidation And Reduction

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Question 35 Report

Which hydrocarbon does NOT exhibit structural isomerism?

C₃H₆ Correct answer

C₄H₆

C₄H₈

C₄H₁₀

C₅H₁₂

Answer Details

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Chemistry Of Carbon Compounds (Nigeria Only)

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Question 36 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

Answer Details

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Atomic Structure And Bonding

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Question 37 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 Correct answer

The colour changes from yellow to orange

There is no visible reaction.

Answer Details

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 38 Report