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Chemistry Past Questions

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2,505 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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2,505 questions

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Question 991

jamb 1989

Using 50 cm\(^3\) of 1 M potassium hydroxide and 100 cm\(^3\) of 1 M tetraoxosulphate (VI) acid, calculate the respective volumes in cm\(^3\) of base and acid that would be required to produce the maximum amount of potassium tetraoxosulphate (IV) [K = 39, S = 32, O = 16, H = 1]

A50, 50

B25, 50

C50, 25

D25, 25

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Question 992

jamb 1989

A hydrated salt of formula MSO4.xH2 O CONTAINS 45.3% by mass of water of crystalisation. Calculate the value of x [M = 56, S = 32, O = 16, H = 1 ]

D10

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Question 993

jamb 1989

Calcium hydroxide is added in the treatment of town water supply to

Akill bacteria in the water

Bfacilitate coagulation of organic particles

Cfacilitate sedimentation

Dimprove the taste of the water

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Question 994

jamb 1989

The gaseous pollutant sulphur (IV)oxide is most likely to be detected in fairly reasonable quantities in the area around a plant for the

Aextraction of aluminium from bauxite

Bproduction of margarine

Csmelting of copper

Dproduction of chlorine from brine

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Question 995

jamb 1989

How many valence electrons are contained in the element represented \(^{31}\) \(_{15}\)P?

C15

D31

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Question 996

jamb 1989

Four elements P,Q, R and S have atomic numbers of 4, 10, 12 and 14 respectively . Which of these electrons is a noble gas?

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Question 997

jamb 1989

The atomic number of caesium is 55 and its atomic mass is 133. The nucleus of caesium atom therefore contains

A78 protons and 55 elections

B55 protons and 78 neutrons

C55 neutrons 78 electrons

D78 protons and 55 neutrons

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Question 998

jamb 1989

Elements X and Y have electronic configurations 1s\(^2\)2s\(^2\)2p\(^4\) and 1s\(^2\)2s\(^2\)2p\(^6\)3s\(^2\)3p\(^1\) respectively. When they combine, the formula of the compound formed is?

AXY

BYX

CX₂Y₃

DY₂X₃

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Question 999

jamb 1989

The atomic radius of Li, Na and K are 1: 33A, 1. 54A and 1. 96A res pectively. Which of the following explaqins this gradation in atomic radius?

Aelectropositivity decreases from Li to Na to K

Belectronegativity decreases from Li to Na to K

Cthe number of the electron shells increases from Li to Na to K

Dthe elements are in the same period

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Question 1000

jamb 1989

What is the partial pressure of hydrogen gas collected
over water at standard atmospheric pressure and 25 ^oC if the saturation vapour pressure of water at saturation vapour pressure of water is 23 mm Hg at that temperature?

A737 mm Hg

B763 mm Hg

C777 mm Hg

D783 mm Hg

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Question 1001

jamb 1989

The minimum volume of oxygen required for the complete combustion of a mixture of 10cm 3 of CO and 15 cm 3 of H 2 is

A25.0cm³

B12.5 cm³

C10.0 cm³

D5.0cm³

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Question 1002

jamb 1989

20.00 cm\(^3\) of a solution containing 0.53 g of anhydrous Na\(_2\)CO\(_3\) in 100 cm\(^3\) requires 25.00 cm\(^3\) of H\(_2\)SO\(_4\) for complete neutralisation. The concentration of the acid solution in moles per dm\(^3\) is [H =1, C = 12, O = 16, Na =23, S = 32]

A0.02

B0.04

C0.06

D0.08

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Question 1003

jamb 1989

The molar ratio of carbon to hydrogen of a volatile liquid compound is 1: 2. 0. 12 g of the liquid on evaporation at s.t.p. gave 32 cm³ of vapour. The molecular formula of the liquid is
[G.M.V =22.4 dm ³, C = 12, H = 1]

AC ₃ H ₆

BC ₄H ₈

CC ₅C ₁₀

DC ₆H ₁₂

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Question 1004

jamb 1989

Which of the following would support the conclusion that a solid sample is a mixture?

Athe solid can be ground to a fine powder

Bthe density of the solid is 2.25 g dm³

Cthe solid has a melting range of 300^oC to 375^oC

Dthe solid absorbs moisture from the atmosphere

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Question 1005

jamb 1988

The acidic hydrogen in the compound is the hydrogen attached to carbon number

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Question 1006

jamb 1988

Carbon (ll) oxide may be collected as shown above because

Ais heavier than air

Bis less dense than air

Cis insoluble in water

Dburns in oxygen to form carbon (IV) oxide

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Question 1007

jamb 1988

The IUPAC name for

A2-methylbutanoic acid

B2-methyl-1- hydroxyketone

C2-methyl-1-hydroxy aldehyde

D2-methylpentanoic acid

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Question 1008

jamb 1988

The diagram above shows the reaction path of an exothermic reaction. The heat of reaction is represented by

Bll

Clll

DlV

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Question 1009

jamb 1988

Use the graph above to answer this question. The mass of a substance, M, liberated at an electrode during electrolysis is proportional to the quantity of electricity, Q passing through the electrolyte. This is represented graphically by.

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Question 1010

jamb 1988

Which of the gas laws does the above graph illustrate?

ABoyle

BCharles

CGraham

DGay-Lussac

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