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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 1021

jamb 1987

The times taken for iodine to be liberated in the reaction between sodium thiosulphate and hydrochloric acid at various temperature are as follows. These results suggest that

Afor a 10^o rise in temperature, rate of reaction is double

Bfor a 10 ^o rise in temperature, rate of reaction is halved

Ctime taken for iodine to appear does not depend on temperature

Dfor a 10 ^o rise in temperature rate of reaction is tripled

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Question 1022

jamb 1987

Use the option above to answer this question. Which is the correct set of results for tests conducted respectively on fresh lime juice and ethanol.

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Question 1023

jamb 1987

An element Z, contained 90% of ¹⁶₈Z and 10% of Z¹⁸₁₈ its relative atomic mass is?

A16.0

B16.2

C17.0

D17.8

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Question 1024

jamb 1987

An isotope has an atomic number of 17 and a mass number of 36. Which of the following gives the correct number of neutrons and protons in an atom of the isotope?

ANeutrons 53, Protons 17

BNeutrons 17, Protons 36

CNeutrons 19, Protons 17

DNeutrons 36, Protons 17

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Question 1025

jamb 1987

If d represents the density of a gas and K is a constant, the rate of gaseous diffusion r is related to d by the equation?

Ar = k/√d

Br = kd

Cr =k/d

Dr = k √d

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Question 1026

jamb 1987

The atomic numbers of two elements X and Y are 12 and 19 respectively. The bond of these two elements is?

Aionic

Bcovalent

CMetallic

Dco-ordinate

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Question 1027

jamb 1987

If 24.83 cm³ of 0.15 M NaOH is titrated to its end point with 39.45 cm³
of HCl, what is the molarity of the HCl?

A0.094 M

B0.150 M

C0.940 M

D1.500 M

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Question 1028

jamb 1987

In which of the following are the aqueous solutions of each of the substances correctly arranged in order to decreasing acidity?

AEthanoic acid, milk or magnesia, sodium chloride, hydrochloric acid and sodium hydroxide

BEthanoic acid, hydrochloric acid, milk of magnesia, sodium chloride and sodium chloride and sodium hydroxide

CHydrochloride acid, ethanol acid, sodium chloride, milk of magnesia and sodium hydroxide

DHydrochloride acid, sodium hydroxide sodium chloride, ethanol acid, and milk of magnesia

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Question 1029

jamb 1987

The solubility of Na3AsO4(H2O)12 is 38.9g per 100g H2O. What is the mass percentage of Na3AsO4 in the saturated solution?

(As = 75, Na = 23, O = 16, H = 1)

A87.27%

B38.9%

C19.1%

D13.7%

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Question 1030

jamb 1987

Oil spillage in ponds and creeks can be cleaned up by?

Aburning off the oil layer

Bspraying with detergent

Cdispersal with compressed air

Dspraying with hot water

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Question 1031

jamb 1987

Which of the following water samples will have the highest titre value when titrated for the Ca²⁺ ions using soap solution?

APermanently hard water after boiling

Bemporarily hard water after boiling

CRain water stored in a glass jar for two years

DPermanent hard water passed through permuitit

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Question 1032

jamb 1987

In the purification of town water supply, alum is used principally to?

Akill bacteria

Bcontrol the pH of water

Cimprove the taste of the water

Dcoagulate small pasrticles of mud

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Question 1033

jamb 1987

A stream of air was successively passed through three tubes X, Y and Z containing a concentrated aqueous solution of KOH, red hot copper powder and fused calcium chloride respectively. What was the composition of the gas emanating from tube Z?

ACO₂ ad ithe inert gases

BN₂, CO₂ and the inert gases

CN₂ and the inert gases

Dwater vapour, N₂ and the inert gases

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Question 1034

jamb 1987

The greater the different in electronegativity between bonded atoms, the?

Alower the polarity of the bond

Bhigher the polarity of the bond

Cweaker the bond

Dhigher the possibility of the substance formed being a molecule

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Question 1035

jamb 1987

When water drops are added to calcium carbide in a container and the gas is passed through a jet and lifted, the resultant flame is called an?

Aoxyethylene flame

Boxyhydrocarbon flame

Coxyacetylene flame

Doxymethane flame

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Question 1036

jamb 1987

Complete oxidation of propan -1- ol gives?

Apropanal

Bpropan-2-al

Cpropan-1-one

Dpropanoic acid

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Question 1037

jamb 1987

Synthetic rubber is made by polymerization of

A2 methyl buta - 1, 3 - diene

B2 methyl buta - 1, 2 - diene

C2 methyl but -1-ene

D2 methyl but-2-ene

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Question 1038

jamb 1987

Local black soap is made by boiling palm oil with liquid extract of ash. The function of the ash is to provide the?

Aacid

Bester of allanoic acid

Calkali

Dalkanol

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Question 1039

jamb 1987

The most volatile fraction obtained from fractional distillation of crude petroleum contains?

Abutane , propane and kerosene

Bbutane , propane and petrol

Cethane, methane and benzene

Dmethane, ethane and propane

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Question 1040

jamb 1987

Ethanol reacts with aqueous sodium mono-oxoio date (l) to give a bright yellow solid with a characteristic smell. The product is?

Atrichloromethane

Btriodomethane

Ciodoethane

Dethanal

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