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Chemistry Past Questions

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47 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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Past Questions

47 questions

Question 1 of 20 47 total questions

Question 1

jamb 1986

When 50cm³ of a saturated solution of sugar (molar mass 342.0g) at 40^oC was evaporated to dryness, 34.2g of dry solid was obtained. The solubility of sugar at 40^oC is

A10.0 moles dm^-3

B7.0 moles dm^-3

C3.5 moles dm^-3

D2.0 moles dm^-3

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Question 2

jamb 1986

Which of the following groups of physical properties increases from left to right of the periodic table?

i. Ionization energy ii. Atomic radius iii. Electronegativity iv. Electron affinity

Ai and ii

Bi, ii and iii

Ciii and iv

Di, iii and iv

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Question 3

jamb 1986

An element with atomic number twelve is likely to be

Aelectrovalent with a velocity of 1

Belectrovalent with a valency of 2

Ccovalent with a valency of 2

Dcovalent with valency of 4

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Question 4

jamb 1986

The relationship between the velocity (U) of gas molecules and their relative molecular mass (M) is shown by the equation

AU = (kM)\(\frac{1}{2}\)

BU = (kM)²

CU = \(\sqrt{\frac{k}{m}}\)

DU = \(\frac{k}{m}\)

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Question 5

jamb 1986

How much of magnesium is required to react with 260cm3 of 0.5 M HCl? [Mg = 24]

A0.3g

B1.5g

C2.4g

D3.0g

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Question 6

jamb 1986

The number of atoms of chlorine present in 5.85g of NaCl is [Avogadro's Number = 6.02 x 10\(^{23}\)]

A6.02 x 10²²

B5.85 x 10²³

C6.02 x 10²³

D5.85 x 10²⁴

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Question 7

jamb 1986

10cm³ of hydrogen fluoride gas react with 5cm³ of dinitrogen difluoride gas (N²F₂) to form 10₃ of a single gas. Which of the following is the most likely equation of the reaction?

AHF + N₂F₂ \(\to\) N₂HF₃

B2HF + N₂F₂ \(\to\) 2NHF₂

C2HF + N₂F₂ \(\to\) N₂H₂F₃

DHF + 2N₂F₂ \(\to\) N₄HF₂

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Question 8

jamb 1986

Use the options above to answer this question. Which is the structural formula for pent-2-enoic acid?

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Question 9

jamb 1986

The tabulated results below were obtained by titration 10.0 cm₃ of water with soup. The titration was repeated with the same sample of water after boiling. The ratio of permanent to temporary hardness is

A1.5

B1.4

C4.1

D5.1

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Question 10

jamb 1986

In the electrolysis of aqueous solution of K₂SO ₄ in the above cell, which species migrate to the anode?

ASO^2-OH ^-

BK ⁺ and SO ₄ ^2-

COH and HO

DH₃O ⁺ and K

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Question 11

jamb 1986

In the solubility curve above, water at 98\(^0\)C is saturated with KCl and KCIO\(_3\). What is the percentage of KCl impurity in the crystals formed when the solution is cooled to 30\(^0\)C?

A51.5

B45.5

C34.5

D26.5

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Question 12

jamb 1986

What mass of a divalent metal M (atomic mass = 40) would react with excess hydrochloric acid to liberate 224cm^3 dry hydrogen gas measured at S.T.P?

A8.0 g

B4.0 g

C0.8 g

D0.4 g

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Question 13

jamb 1986

The movement of liquid molecules from the surface of the liquid to the gaseous phase above it is known as?

ABrownian movement

Bcondensation

Cevaporation

Dliquefaction

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Question 14

jamb 1986

Starch can be converted to ethyl alcohol by?

Adistillation

Bfermentation

Cisomerization

Dcracking

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Question 15

jamb 1986

Which of the following are made by the process of polymerization?

ANylon and soap

BNylon and artificial rubber

CSoap and butane

DMargarine and nylon

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Question 16

jamb 1986

The general formula of an alkyl halide (where X represents the halide) is?

AC_nH_2n ₂X

BC_nH_2n + ₁X

CC_nH_2n + ₂X

DC_nH_2nX

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Question 17

jamb 1986

Which of the following substance is a mixture?

AGranulated sugar

BSea-water

CSodium chloride

DIron fillings

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Question 18

jamb 1986

Which of the following compounds is NOT formed by the action of chlorine on methane?

ACH₃CI

BC₂H₅CI

CCH₂CI₂

DCHCI₃

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Question 19

jamb 1986

When ethanol is heated with excess concentrated sulphuric acid, the ethanol is?

Aoxidized to ethene

Bpolymerized to polyethene

Cdehydrated to ethene

Ddehydrated to ethyne

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Question 20

jamb 1986

What reaction takes place when palm-oil is added to potash and foam are observed?

ANeutralization

BSaponification

CEsterification

DSalting-out

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