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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.

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

2,505 questions
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Question 1 of 20 2,505 total questions
Question 821
jamb 1997

If 30cm\(^3\) of oxygen diffuses through porous plug in 7s, how long will it take 60 cm\(^3\) of chlorine to diffuse through the same plug?

A12s
B14s
C21s
D30s
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Question 822
jamb 1997

Oxygen is a mixture of two isotopes 16-O and 18-O with relative abundances of 90% and 10% respectively. The relative atomic mass of oxygen is?

A16.0
B16.2
C17.0
D18.0
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Question 823
jamb 1997
Two elements, P and Q with atomic numbers 11 and 8 respectively , combine chemically to form the compound PxQY. The respective values of x and y are?
A1 and 1
B1 and 2
C2 and 1
D3 and 1
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Question 824
jamb 1997
In the periodic table, what is the property that decreases along the periodic and increases down the group?
AAtomic number
BElectron affinity
CIonization potential
DAtomic radius
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Question 825
jamb 1997
The electron configuration of two elements with similar chemical properties are represented by?
A1s22s22p5 and 1s22s22p4
B1s22s22p4 and 1s22s22p63s1
C1s22s22p63s1 and 1s22s1
D1s22s22p4 and 1s22s1
View Explanation & Discuss
Question 826
jamb 1997
The temperature of a body decreases when drops of liquid placed on it evaporate because?
Athe atmospheric vapour pressure has a cooling effect on the body
Ba temperature gradient exists between the drops of liquid and the body causing the latter to vaporate
Cthe heat of vapourization is drawn from the body causing it to cool
Dthe random motion of the liquid molecules causes a cooling effect on the body
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Question 827
jamb 1997
A mixture of 0.20 mole of Ar, 0.20 mole of N2 and 0.30 mole of He exerts a total pressure of 2.1 atm. The partial pressure of He in the mixture is?
A0.90 atm
B0.80 atm
C0.70 atm
D0.60 atm
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Question 828
jamb 1997
An element, X, forms a volatile hydride XH3 with a vapour density of 17.0. The relative atomic mass of X is?

(H = 1)
A34.0
B31.0
C20.0
D14.0
View Explanation & Discuss
Question 829
jamb 1997
2.85g of an oxide of copper gave 2.52g of copper on reduction and 1.90g of another oxide gave 1.52g of copper on reduction. The data above illustrates the law of?
Aconstant composition
Bconservation of mass
Creciprocal proportions
Dmultiple proportions
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Question 830
jamb 1997

35 cm3 of hydrogen was sparked with 12 cm3 of oxygen at 110°C and 760mm Hg to produce steam. What percentage of the total volume of gas left after the reaction is hydrogen?

A11%
B31%
C35%
D69%
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Question 831
jamb 1995

The functional group represented in the compound above is?

Aalkanol
Balkanal
Calkanone
Dalanoate
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Question 832
jamb 1995

The option above shows the PH changes for the titration of a

Astrong acid versus strong base
Bweak acid versus strong base
Cstrong acid versus weak base
Dweak acid versus weak base
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Question 833
jamb 1995

It can be deduced that the rate of the reaction?

Afor path l is higher than path ll
Bfor path ll is higher than path l
Cis the same for both paths at all temperatures
Ddepends on the values of both x and y at all pressures
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Question 834
jamb 1995

Use the diagram above to answer this question. The activation energy of the uncatalysed reaction is

AX
BX + Y
CX - Y
DY
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Question 835
jamb 1995

The arrangement above can be used for the collection of

Asulphur (IV) oxide
Bammonia
Chydrogen chloride
Dnitrogen
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Question 836
jamb 1995
USE THE SECTION OF THE PERIODIC TABLE ABOVE TO ANSWER THIS QUESTION.Which letter represents a non-metal that is a solid at room temperature?
AT
BR
CJ
DX
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Question 837
jamb 1995

USE THE SECTION OF THE PERIODIC TABLE ABOVE TO ANSWER THIS QUESTION.Which of the indicate an alkali metal and a noble gas respectively?

AM and E
BG and E
CR and L
DG and L
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Question 838
jamb 1995
The relatively high boiling points of alkanols are due to?
Aionic bonding
Baromatic character
Ccovalent bonding
Dhydrogen bonding
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Question 839
jamb 1995
An example of a secondary amine is?
Apropylene
Bdi-butylamine
Cmethylamine
Dtrimethylamine
View Explanation & Discuss
Question 840
jamb 1995
CxHY + 4O2 → 3CO2 + 2H2O. The hydrocarbon, CxHY, in the reaction above is?
Apropane
Bpropene
Cpropyne
Dpropanone
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