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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 91

waec 2024

According to the collision theory of reaction rates, which of the following conditions is not required for two molecules to react? The molecules must

Acome into contact without loss of energy on colliding with each other

Bcollide with enough energy to overcome the activation energy barrier

Ccollide in an orientation that makes formation of product possible

Dpossess enough speed to overcome intermolecular forces of attraction

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Question 92

waec 2024

The following organic compounds are polymers except

Arubber

Bstarch

Cproteins

Dfats

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Question 93

waec 2024

A saturated solution at 30\(^0\)C will normally produce crystals at a temperature of

A50\(^0\)C

B40\(^0\)C

C35\(^0\)C

D20\(^0\)C

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Question 94

waec 2024

Ethane of volume 400 cm\(^3\) was completely burnt in excess oxygen according to the following equation:

2C\(_2\)H\(_6\)\(_(g)\) + 7O\(_2\)\(_(g)\) → 6H\(_2\)O\(_(g)\) + 4CO\(_2\)\(_(g)\)

Calculate the volume of steam that would be produced.

A200 cm\(^3\)

B400 cm\(^3\)

C600 cm\(^3\)

D1200 cm\(^3\)

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Question 95

waec 2024

Catalysts alter reaction rates by

Aproviding an alternative reaction pathway

Blowering the energy of reaction

Cincreasing the surface area of reactants

Daligning the reactant molecules properly

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Question 96

waec 2024

The percentage by mass of Oxygen in MgSO\(_4\).7H\(_2\)O is [ M\(_r\) of MgSO\(_4\).7H\(_2\)O = 246 ]

A26.0%

B45.5%

C71.5%

D84.0%

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Question 97

waec 2024

Which of the following household liquids would be effective in treating someone with too much acid in the stomach?

AStrong salt solution with pH 7.0

BTomato juice with pH 4.1

CMilk of Magnesia with pH 10.5

DBlack coffee with pH 5.0

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Question 98

waec 2024

Isotopes of the same element have similar chemical properties because they have the same number of

Anuclides

Bprotons

Cneutrons

Datoms

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Question 99

waec 2024

The number of shared pair of electrons in a molecule of methane is

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Question 100

waec 2024

Naturally occurring Boron is made up of 19.9% \(^{10}\)B and 80.1% \(^{11}\)B. The relative atomic mass of Boron is

A21.0

B10.8

C10.5

D10.0

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Question 101

waec 2024

Consider the reaction represented by the equation:

C\(_3\)H\(_8\) + 5 O\(_2\) → 3CO\(_2\) + 4H\(_2\)O

If 0.1 mole of C\(_3\)H\(_8\) was completely burnt, what volume of CO\(_2\) would be produced at stp? [volume of gas at stp = 22.4dm\(^3\)mol\(^{-1}\)].

A6.72dm\(^3\)

B2.24dm\(^3\)

C0.30 dm\(^3\)

D0.10dm\(^3\)

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Question 102

waec 2024

Which of the following arrangements of elements is in order of increasing ionization energy?

ASi, Al, S, P

BS, P, Si, Al

CAl, Si, P, S

DP, Si, S, Al

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Question 103

waec 2024

Aluminium is suitable for making alloys for aircraft construction because it

Ais hard and brittle

Bis light and very resistant to corrosion

Chas high density and also a non-conductor of electricity

Dis amphoteric and allotropic

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Question 104

waec 2024

Which of the following statements describes transition elements? They

Aare very reactive

Bhave low melting points

Cpossess variable oxidation state

Dform colourless salts

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Question 105

waec 2024

The reaction represented by the equation: Ni\(^{2+}\)\((_{aq}\)) + Fe\((_s\)) → Ni\((_s\)) + Fe\(^{2+}\)\((_{aq}\)) is a redox reaction because

ANi\(^{2+}\) ions are oxidized and Fe acts as a oxidizing agent

BNi\(^{2+}\) ions are oxidized and Fe acts as a reducing agent

CNi\(^{2+}\) ions are reduced and Fe acts as an oxidizing agent

DNi\(^{2+}\) ions are reduced and Fe acts as a reducing agent.

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Question 106

waec 2024

At 25\(^0\)C, the saturated solution of a salt in water was found to contain 0.24g of the salt in 100cm\(^3\). What is the solubility of the salt in gdm\(^{-1}\)?

A0.024

B0.240

C2.40

D24.0

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Question 107

waec 2024

In ethanol, the attractive forces between adjacent molecules are

Acovalent bonds only

Bhydrogen bonds only

Chydrogen bonding and Van der Waal's forces

DVan der Waal's forces only

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Question 108

waec 2024

Which of the following functional groups is present in alkanoic acid?

A-COOH

B-OH

C-COOR

D-CHO

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Question 109

waec 2024

Ethanedioic acid is an organic solid that can be purified by

Adecantation

Bdistillation

Ccrystallization

Dfiltration

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Question 110

waec 2024

Which of the following statements about ammonium salt is correct? It

Adissolves in water to form solution of pH > 1

Bdissolves in water to form solution of pH < 7

Cdoes not decompose on heating

Dis insoluble in water

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