Chemistry Past Questions

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

2,505 questions
Question 1 of 20 2,505 total questions
Question 891
jamb 1993
During the electrolysis of a salt of a metal M, a current of 0.5 A flows from for 32 minutes 10 seconds and deposits 0.325 g of M, What is the charge of the metal ion?

(M = 65, If = 96,500 C per mole of electron)
A1
B2
C3
D4
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Question 892
jamb 1993
4.0 g of sodium hydroxide in 250 cm3 of solution contains?
A0.40 moles per dm3
B0.10 moles per dm3
C0.04 moles per dm3
D0.02 moles per dm3
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Question 893
jamb 1993

NH\(_3\)  +  H\(_3\)O\(^+\) → NH\(_4\)\(^+\) + H\(_2\)O. It may be deduced from the reaction above that?

Aa redox reaction has occurred
BH3O+ acts as an oxidizing agent
CH3O+ acts as an acid
Dwater acts as an acid
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Question 894
jamb 1993

A student prepares 0.5 M solution each of hydrochloric and ethanoic acids and then measured pH. The result would show that the?

ApH values are equal
BHCI solution has a higher pH
Csum of the values is 14
Dethanoic acid solution has a higher pH
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Question 895
jamb 1993
The phenomenon whereby sodium trioxocarbonate (IV) decahydrate loses some of its water of crystallization on exposure to the atmosphere is known as?
Adeliquescene
Bhygroscopy
Ceffervescence
Defflorescence
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Question 896
jamb 1993
Water can be identified by the use of?
Aanhydrous copper (II) tetraoxosulphate (VI)
Banhydrous sodium trioxocarbonate (IV)
Cpotassium heptaoxochromate (VII)
Dcopper (II) trioxocaronate (IV)
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Question 897
jamb 1993
The air around a petroleum refinery is most likely to contain?
ACO2, SO3 and N2O
BCO2, CO and N2O
CSO2, CO and NO2
DPH3 H2O and CO2
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Question 898
jamb 1993

Argon is used in gas-filled electric lamp because it helps to?

Aprevent the reduction of the lamp fillaments
Bprevent oxidation of the lamp fillaments
Cmake the lamp fillament glow brightly
Dkeep the atmosphere in the lamp inert
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Question 899
jamb 1993
Water has a rather high boiling point despite its low molecular mass because of the presence of?
Ahydrogen bonding
Bcovalent bonding
Cionic bonding
Dmetallic bonding
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Question 900
jamb 1993

Which group of elements forms hydrides that are pyramidal in structure?

AIII
BIV
CV
DVI
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Question 901
jamb 1993
As the difference in electronegativity between bonded atoms increases, polarity of the bond?
Adecreases
Bincreases
Cremains unchanged
Dreduces to zero
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Question 902
jamb 1993
Two atoms represented as U and U are?
Aisomers
Ballotropes
Cisotopes
Danomers
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Question 903
jamb 1993
An element, E, has the electronic configuration 1s22s22p63s2p3. The reaction of E with a halogen X can give?
AEX3 and EX5
BEX3 only
CEX5 only
DEX2 and EX3
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Question 904
jamb 1993
For iodine crystals to sublime on heating, the molecules must acquire energy that is?
Aless than the forces odf attraction in the solid
Bequal to the forces of attraction in th solid
Cnecessary to melt the solid
Dgreater than the forces of attraction in both the solid and the liquid phases
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Question 905
jamb 1993
How many moles of oxygen molecules would be produced from the decomposition of 2.50 moles of potassium trioxochlorate (V)?
A2.50
B3.50
C3.75
D7.50
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Question 906
jamb 1993
A balanced chemical equation obeys the law of?
Aconservation of mass
Bdifinite proportions
Cmultiple proportions
Dconservation of energy
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Question 907
jamb 1993

Which of the following substances is a mixture?

ASulphur powder
BBronze
CDistilled water
DEthanol
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Question 908
jamb 1992
The nucleus of the isotopes tritium,contains
Atwo neutrons with no protons
Bone neutron and one proton
Ctwo neutrons and one proton
Dtwo neutrons, one proton and one electron
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Question 909
jamb 1992
A given mass of gas occupies 2 dm2 at 300k. At what temperature will its volume be doubled keeping the pressure constant?
A400k
B480k
C550k
D600k
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Question 910
jamb 1992

Which of the following compounds is a secondary alkanol?

AA
BB
CC
DD
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