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Chemistry Past Questions

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4,306 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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4,306 questions

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Question 1081

jamb 2007

H\(_3\)PO\(_4\)(aq) + H\(_2\)O(l) ↔ H\(_2\)PO\(^{4-}\)(aq) + H\(_3\)O\(^+\)(aq) ΔH = -13kJ at 298K
In the reaction above, an increase in temperature would

Aslow down the reverse reaction

Bhave no effect on the reaction

Cfavour the reverse reaction

Dfavour the forward reaction

View Explanation & Discuss

Question 1082

jamb 2007

If chlorine is bubbled into water and the resulting yellowish-green solution is exposed to bright sunlight for a while, the solution will decompose giving out

Aoxygen and leaving behind aqueous hydrochloric acid

Bchlorine and oxygen

Coxygen, hydrogen and chlorine

Doxygen, thereby producing hypochlorous acid

View Explanation & Discuss

Question 1083

jamb 2007

Which of the following sets of metals dissolves in dilute HCl?

AFe, Sn and Cu

BMg, Fe and Cu

CMg, Sn and Fe

DCu, Mg and Sn

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Question 1084

jamb 2007

Copper and silver metals are commonly used as coin because they are

Aeasily reduced

Bnot easily reduced

Ceasily oxidized

Dnot easily oxidized

View Explanation & Discuss

Question 1085

jamb 2007

Cu\(^{2+}\)(aq) + 4NH\(_3\)(g) ↔ [Cu(NH\(_3\))\(_4\)]\(^{2+}\)(aq)
In the reaction above, what is the effect of precipitating Cu\(^{2+}\)(aq) as CuS(s)?

ANH_3(g) concentration will decrease

Bmore NH_3(g)

CThe equilibrium will shift to the right

DThere will be no effect

View Explanation & Discuss

Question 1086

jamb 2007

The tincture of iodine means iodine dissolved in

Aethanol and water

Bbromine chloride

Cchlorine water

Dwater

View Explanation & Discuss

Question 1087

jamb 2007

Na\(_2\)S\(_2\)O\(_3\)(aq) + 2HCl(aq) → 2NaCl(aq) + H\(_2\)O(l)
Which of the following would introduce the greatest increase in the rate of the chemical reaction above?

AAn increase in temperature and decrease in the concentration of the reactant

BA decrease in the volume and increase in the pressure of the reactant

CA decrease in the temperature and an incease in the concentration of the reactant

DAn increase in temperature and an increase in the concentration of the reactant

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Question 1088

jamb 2007

The reddish-brown rust on iron roofing sheets consists of

AFe³⁺(H₂O)₆

BFeO.H₂O

CFe₂O₃.3H₂O

DFe₃O₄.2H₂O

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Question 1089

jamb 2007

The soft solder used for welding and plumbing is alloy of

Alead and tin

Biron and tin

Clead and zinc

Diron and zinc

View Explanation & Discuss

Question 1090

jamb 2007

A solution which on treatment with hydrochloric acid produces a colourless, odourless gas which turns lime water milky is most likely to be a

Atrioxonitrate (V)

Bchloride

Ctrioxocarbonate (IV)

Dhydroxide

View Explanation & Discuss

Question 1091

jamb 2007

When calcium oxide is heated with carbon, the oxide will

Abe converted to carbide

Bbe converted to the trioxocarbonate (IV) salt

Cdecompose to the metal

Dmelt, producing carbon (IV) oxide

View Explanation & Discuss

Question 1092

jamb 2007

An element used in the production of matches is

Anitrogen

Baluminium

Ccopper

Dsulphur

View Explanation & Discuss

Question 1093

jamb 2007

Trioxonitrate (V) acid is not used for preparing hydrogen gas from metals because it

Ais strongly oxidizing

Bis volatile

Crenders the metal passive

Dforms a layer of oxide on the metal

View Explanation & Discuss

Question 1094

waec 2006

Which of the following equations represents a substitution reaction?

AC ₂H_10(g) + CI _2(g) → C₄H₉ CI_(g) + HCI_(g)

BC ₂H_4(g) + HCI _(g) → C ₂H₅ CI_(l)

CC₂H_2(g) + 2H _2(g) → C ₂H_6(g)

DC ₃H_4(g) + 40_2(g) → 3CO_2(g) + 2H ₂O_(g)

View Explanation & Discuss

Question 1095

waec 2006

The ammonium compound used in the manufacture of dry cells is

ANH₄NO₃

B(NH₄)SO₄

CNH₄Cl

D(NH₄)₂CO₃

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Question 1096

waec 2006

Which of the following substance is an ore of iron?

ABauxite

BCassiterite

CHaematite

DSteel

View Explanation & Discuss

Question 1097

waec 2006

Waste plastics accumulate in the soil and pollute the environment because plastic materials are

Ainsoluble in water

Bnon -biodegradable

Ceasily affected by heat

Dinflammab,le

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Question 1098

waec 2006

Greenhouse effect can be reduced by controlling

Awater evaporation

Bburning wood and fossil fuel

Cthe use of aerosols

Dthe use of artificial fertilizers

View Explanation & Discuss

Question 1099

waec 2006

What is C_aH_b in the following equation? C _a
H _b + 5O₂ → 3CO ₂ + 4H₂O

AC ₃H₄

BC₃H₆

CC₃H₈

DC ₅H ₁₀

View Explanation & Discuss

Question 1100

waec 2006

Which of the following compounds is an alkanoate?

ACH₃COOH

BCH₃COOCH₃

CCH₃CH₂OH

DCH₃CH₂COOH

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