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Chemistry Past Questions

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90 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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90 questions

Question 1 of 20 90 total questions

Question 11

waec 2021

The 25°C evaporation of a 100 cm\(^{3}\) solution of K\(_{2}\)CO\(_{3}\) to dryness gave 14g of the salt. What is the solubility of K\(_{2}\)CO\(_{3}\) at 25°C? [K\(_{2}\)CO\(_{3}\) = 138]

A0.01 mol dm\(^{-3}\)

B0.101 mol dm\(^{-3}\)

C1.01 mol dm \(^{-3}\)

D10.0 mol dm\(^{-3}\)

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Question 12

waec 2021

The Bohr model of the atom proposed the existence of?

Athe nucleus

Belectron shells

Cnucleons

Dneutrons

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Question 13

waec 2021

How many coulombs of electricity would liberate 1.08g of Ag from a solution of silver salt?

[Ag = 108.0; 1F = 96500 C]

A96500 C

B9650 C

C965 C

D9.65 C

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Question 14

waec 2021

The reactivity of fluorine is high because of

Aits high electronegativity

Bthe small size of the fluorine atom

Cthe availability of d-orbitals

Dthe strong F-F bond

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Question 15

waec 2021

Which of the following half reaction equations represent the reaction at the cathode

AA\(^{3+_{(aq)}}\)+3e\(^{-}\) \(\rightarrow\) A\(_{(s)}\)

BB\(^{2+_{(aq)}}\)+2e\(^{-}\) \(\rightarrow\) B\(_{(s)}\)

CA\(_{(s)}\) \(\rightarrow\) \(^{3+_{(aq)}}\)+3e\(^{-}\)

DB\(_{(s)}\) \(\rightarrow\) B\(^{2+_{(aq)}}\) + 2e\(^{-}\)

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Question 16

waec 2021

Which of the following cell notations represent the diagram?

AB\(^{2+}\)/B/ /A/A\(^{3+}\)

BA\(^{3+}\) /A/ /B/B\(^{2+}\)

CB/B\(^{2+}\)/ /A/\(^{3+}\)

DA/A\(^{3+}\)/ /B\(^{2+}\)/B

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Question 17

waec 2021

Which of the following statements about Group VII elements is correct?

Athey are present in the same physical state

Bthey are strong reducing agents

Ctheir reactivity decreases down the group

Dthey exist as monoatomic molecules

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Question 18

waec 2021

Elements with high ionization energies would-------

Alose electrons easily

Bhave large atomic radii

Chave high effective nuclear charges

Dhave low atomic numbers

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Question 19

waec 2021

The collision between ideal gas molecules are considered to be perfectly elastic because

Athey collide without losing energy

Bthey move randomly in a straight line

Ctheir average kinetic energy is variable

Dthe distance between them is large compared to their size

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Question 20

waec 2021

Under which conditions of pressure (p) and temperature (T) would the volume of an inflated ballon increase? When

AP and T are increased

Bboth T and P are decreased

CT is increased and P is decreased

DT is decreased and P is increased

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Question 21

waec 2021

Consider the structure above

How many carbon atoms does the parent chain contain?

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Question 22

waec 2021

When CuSO\(_{4(aq)}\) is added to Pb(NO\(_{3}\))\(_{2(aq)}\)--------

Athere would be no visible change

Ba blue precipitate would be formed

Cthe resulting solution would become colourless

Da white precipitate would be formed

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Question 23

waec 2021

What would be observed when aqueous ammonia is added in drops and then in excess to a solution of copper(II) ions?

Ablue precipitate is formed which is soluble in excess ammonia

Bbrick red precipitate is produced which is insoluble in excess ammonia

Cwhite precipitate is formed which is excess in ammonia

Dgreen precipitate is formed which is insoluble in excess ammonia

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Question 24

waec 2021

The basic property of salts used as drying agents is by?

Aefforescence

Bhigh melting point

Chygroscopy

Dlow solubility

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Question 25

waec 2021

What number of moles of oxygen would exert a pressure of 10 atm at 320 K in an 8.2 dm\(^{2}\) cylinder?

[R = 0.082 atm dm\(^{3}\) mol\(^{-1}\) K\(^{-1}\)]

A0.32

B1.56

C3.13

D31.25

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Question 26

waec 2021

The most common method of preparing insoluble salts is by

Afiltration

Bdecomposition

Cneutralization

Ddouble decomposition

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Question 27

waec 2021

A molecular of phosphorus is

Adiatomic

Btriatomic

Ctetraatomic

Dmonoatomic

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Question 28

waec 2021

Which of the following gasses is highly soluble in water at room temperature

Aammonia

Bcarbon (IV) oxide

Cchlorine

Dnitrogen

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Question 29

waec 2021

The formation of ethene from dehydration of ethanol can be described as-------

Aan addition reaction

Ban elimination reaction

Can oxidation reaction

Da substitution reaction

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Question 30

waec 2021

Which of the graphs illustrates the variation of the solubility of a salt in water (y-axis), with an increase in temperature (x-axis) if the dissolution process is exothermic?

BII

CIII

DIV

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