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Chemistry Past Questions

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84 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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84 questions

Question 1 of 20 84 total questions

Question 31

jamb 1991

MnO^-₄ + 8H⁺ + ne → Mn⁺⁺ + 4H₂O. Which is the value of n in the reaction above?

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Question 32

jamb 1991

Which of the following equimolar solutions, Na₂CO₃ Na₂ SO
₄CI FeCI₃ CH₃COONa,
have pH greater than 7?

AFeCI ₃ and NH ₄CI

BNa₂CO₃, CH₃COONa and Na,Na₂SO₄

CNa₂CO₃ and CH₃COONa

DFeCI₃, CH₃COONa and NH₄CI

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Question 33

jamb 1991

If a current of 1.5 A is passed for 4.00 hours through a molten tin salt and 13.3g of tin is deposited, what is the oxidation state of the metal in the salt?

(Sn = 118.7, F = 96500 C mol^-1)

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Question 34

jamb 1991

What volume of CO\(_2\) at s.t.p would be obtained by reacting 10cm\(^3\) of 0.1M solution of anhydrous sodium trioxocarbonate (IV) with excess acid?

(G.M.V at s.t.p = 22.4 dm\(^3\))

A2.240 cm ³

B22.40 cm ³

C224.0 cm ³

D2240 cm ³

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Question 35

jamb 1991

How many structural isomers can be written for the alkyl bromide, C₄H₉Br?

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Question 36

jamb 1991

50 cm\(^3\) of sulphur (IV) oxide, 800cm\(^3\) of ammonia, 450 cm\(^3\) of hydrogen chloride, 1.0 cm\(^3\)of Carbon(IV) oxide will respectively saturate 1.0 cm\(^3\) of water at 15°C. Which of the following is suitable for demonstrating the fountain experiment?

ASulphur (IV) oxide and hydrogen chloride

BCarbon (IV) oxide and ammonia

CAmmonia and hydrogen chloride

DCarbon (IV) oxide and surphur (IV) oxide

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Question 37

jamb 1991

A property of a colloidal dispersion which a solution does not have is?

Athe Tyndall effect

Bhomogeneity

Cosmotic pressure

Dsurface polarity

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Question 38

jamb 1991

A sample of temporary hard water can be prepared in the laboratory by?

Adisolving calcium chloride in distilled water

Bsaturating lime water with carbon (IV) oxide

Csaturating distilled water with calcium hydroxide

Ddissolving sodium hydrogen trioxocarbonate (IV) in some distilled water

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Question 39

jamb 1991

The solubility of copper (II) tetraoxosulphate (Iv) is 75g in 100g of water at 100°C and 25g in 100g of water at 30°C. What mass of the salt would crystallize, if 50g of copper (II) tetraoxosulphate (VI) solution saturated at 100°C were cooled to 30°C ?

A57.5

B42.2

C28.6

D14.3

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Question 40

jamb 1991

Which of the following ions is a pollutant in drinking water even in trace amounts?

ACa²⁺

BHg²⁺

CMg²⁺

DFe²⁺

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Question 41

jamb 1991

A quantity of air was passed through a weighed amount of alkaline pyrogallol. An increase in the weight of the pyrogallol would result from the absorption of?

Anitrogen

Bneon

Cargon

Doxygen

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Question 42

jamb 1991

Which of the following is arranged in order of increasing electronegativity?

AChlorine, aluminium, magnesium, phosphorus, sodium

Bsodium, magnesium, aluminium, phosphorus, chlorine

CChlorine, phosphorus, phosphorous, aluminium, magnesium, sodium

DSodium, chlorine, phosphorus, magnesium, aluminium

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Question 43

jamb 1991

Which of the following represents the type of bonding present in ammonium chloride molecule?

AIonic only

BCovalent only

CIonic and dative covalent

DDative covalent only

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Question 44

jamb 1991

The ions X_- and Y₊ are isoelectronic, each containing a total of 10 electrons.
How many protons are in the nuclei of the neutral atoms of X and Y respectively?

A10 and 10

B9 and 9

C11 and 9

D9 and 11

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Question 45

jamb 1991

The electronic configuration of an elements is 1s22s22p63s23p3. How many unpaired electrons are there in the element?

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Question 46

jamb 1991

Atoms of element X (with 2 electrons in the outer shell). combine with atoms of Y (with 7 electrons in the outer shell). Which of the following statements is FALSE? The compound formed?

Ahas formula XY

Bis likely to be ionic

Ccontains X²⁺ ions

Dcontains Y^- ions

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Question 47

jamb 1991

A sample of a gas exerts a pressure of 8.2 atm when confined in a 2.93 dm³ container at 20°C. The number of moles of gas in the sample is?

(R = 0.082 litre atm / deg mole)

A1.00

B2.00

C3.00

D4.00

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Question 48

jamb 1991

A given quantity of a gas occupies a volume of 228 cm³ at a pressure of 750mm Hg. What will be its volume at atmospheric pressure?

A220 cm³

B225 cm³

C230 cm³

D235 cm³

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Question 49

jamb 1991

Calculate the volume of carbon (IV)oxide measured at s.t.p, produced when 1 kg of potassium hydrogen trioxocarbonate (IV) is totally decomposed by heat?

(G.M.V. at s.t.p 22.4 dm³, K = 39, O = 16, C = 12, H = 1)

A28 dm³

B56 dm³

C112 dm³

D196 dm³

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Question 50

jamb 1991

30cm\(^3\) of oxygen at 10 atmospheres pressure is placed in a 20 cm\(^3\) container. Calculate the new pressure if temperature is kept constant?

A6.7 atm

B15.0 atm

C60.0 atm

D66. 0 atm

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