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Chemistry Past Questions

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1,623 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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1,623 questions

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Question 791

waec 1989

120cm\(^3\) of hydrogen were sparked with 60cm\(^3\) of oxygen at 110\(^o\)C. What was the volume of steam produced? The equation for the reaction is

2H\(_2\)(\(_g\) + O\(_2\)(\(_g\) → 2H\(_2\)O\(_g\)

A30cm³

B60cm³

C90cm³

D120cm³

E180cm³

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Question 792

waec 1989

Which of the following statements best explains cracking ? It is a process

Ain which an alkene adds on itself repeatedly to form long chain polymers

Bin which large hydrocarbon molecules are broken into smaller units

Cfor measuring theoctane number of petrol

Din which carbon chain results in a zigzag arrangement

Ein which aromatic hydrocarbons are produced

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Question 793

waec 1989

Which of the following reactions represents the laboratory preparation of hydrogen?

AC_(s) + H₂O_(l) → CO_(g) + H_2(g)

B2Na_(s) + 2H₂O_(l) → 2NaOH_(aq) + H_2(g)

CZn_{(s) + 2HCI_(aq) → ZnCI_2(aq) + H_2(g)}

DCu_(s) + H₂O_(l) → CuO_(s) + H_2(g)

E2AI_(s) + 3H₂O_{(l) → Al₂O_3(s) + 3H_2(g)}

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Question 794

waec 1989

The major raw material in a plastic industry is

Aethanol

Bsulphur

Cmethylethanoate

Dethene

Eethane

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Question 795

waec 1988

During the electrolysis of dilute tetraoxosulphate (VI) acid solution 0.05 mole of electrons were passed what volume of gas was produced at the anode? (Gaseous molar volume = 22. 4dm³ at s.t.p)

A0.224 dm³

B0.280 dm³

C0.560 dm³

D2.24 dm³

E22.4 dm³

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Question 796

waec 1988

The reaction represented by the equation C_(s) + H₂O_(l) → CO_(s) + H ₂_(s) was carried out at 27_oC if the enthalpy change was + 4500 J and the entropy change was + 12J, what was the free energy change? (∆G = ∆H - T∆S)

A- 4176 J

B+4176 J

C- 900 J

D+ 900 J

E+8100 J

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Question 797

waec 1988

The complex salt formed when aluminium dissolves in sodium hydroxide solution is

ANa₃AI(OH)₄

BNa₂AI(OH)3

CNaAI(OH)₃

DNa₄AI(OH)₄

ENaAI(OH)₄

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Question 798

waec 1988

When copper (ll) chloride solution is treated with excess aqueous ammonia, a deep blue solution results This is due to the presence of

A(CuNH₄)³⁺ ions

B(CuCI₄)^2-ions

C[Cu(OH)₄]^2- ions

DCu(H^2-O)₄²⁺ IONS

E[cU(NH₃)₄]^ions

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Question 799

waec 1988

Which of the following is a waste product in the Solvary Process for the manufacture of sodium trioxocarbonate (IV)?

AAmmonium chloride

BBrine

CLimestone

DCalcium oxide

ECalcium chloride

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Question 800

waec 1988

Which of the following correctly explains why iodine crystals change directly into the gaseous state when heated?

Alodine crystals sublime

Blodine atoms are held together by strong forces

Clodine molecules are held together by weak forces

Dlodine molecules are covalent

Elodine is a solid at room temperature

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Question 801

waec 1988

Aqueous sodium trioxocarbonate (IV) solution is alkaline because

Aacid from which it is formed is strong

Bsodium is an alkali metal

Csodium trioxocarbonate (IV) is decomposed by water

Dsodium trioxocarbonate (lV) is stable to heat

Esodium triocarbonate (IV) is hydrolysed in water

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Question 802

waec 1988

Which of the following equations represents the reaction of chlorine with hot concentrated sodium hydroxide solution?

A2NaOH+CI₂ → NaCIO + NaCI + H₂O

B4NaOH + 2CI → 4NaCI + 2H₂O + O₂

C6NaOH + 3CI₂ → NaCIO₃ + 5NaCI + 3H₂O

D2NaOH + CI₂ → 2NaCI + H₂O₂

ENaOH + 2CI₂ + H₂O → NaCI + 3HCI + O₂

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Question 803

waec 1988

Which of the following is not a naturally occurring iron ore?

AFeCl₂

BFe₃O₄

CFe₂O₃

DFeCO₃

EFeS₂

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Question 804

waec 1988

Which of the following metals cannot extracted from its ore by using carbon (ll) oxide as the reducing agent?

ACu

BZn

CAl

DPb

EFe

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Question 805

waec 1988

Water gas is a mixture of?

ACO_{2 and H₂}

BCO and H₂O

CCO₂ and CO

DCO and N₂

ECO and H₂

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Question 806

waec 1988

How many isomers can be obtained from C_4H₁₀?

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Question 807

waec 1988

What volume of oxygen will be left unreacted when a mixture of 100cm³ of hydrogen and 200cm,sup>3,/sup> of oxygen are exploded in a eudiometer?

A300cm³

B200cm³

C150cm³

D100cm³

E50cm³

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Question 808

waec 1988

Which of the following is not true of the rusting of iron?

ARusting is a reduction process

BRusting of iron takes place in the presence of oxygen and moisture

Cthe rust formed is reddish brown

Dthe major constituent of rust is hydrated iron (lll) oxide

Erusting is similar to burning

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Question 809

waec 1988

Which of the following is not true of the rusting of iron?

ARusting is a reduction process

BRusting of iron takes place in the presence of oxygen and moisture

Cthe rust formed is reddish brown

Dthe major constituent of rust is hydrated iron (lll) oxide

Erusting is similar to burning

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Question 810

waec 1988

Which of the following is not decomposed by heat?

ACaCO₃

BCuCO₃

CZnCO,sub>3

DNa₂CO₃

EMgCO₃

View Explanation & Discuss

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