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Chemistry Past Questions

Study and practice Chemistry past questions with answers and detailed explanations. Then test your knowledge using our interactive CBT practice platform and prepare confidently for your upcoming examinations.

49 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10
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Past Questions

49 questions
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Question 1 of 9 49 total questions
Question 21
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?
AP
BQ
CR
DS
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Question 22
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 23
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 24
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 25
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 26
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 27
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 28
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 29
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 300oC to 375oC
Dthe solid absorbs moisture from the atmosphere
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