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Chemistry Past Questions

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49 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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Past Questions

49 questions

Question 1 of 20 49 total questions

Question 11

jamb 2017

Cu\(_2\)S(g) + O\(_2\)(g) → 2Cu + SO\(_2\)(g)
What is the change in the oxidation number of copper in the reaction?

A0 to + 2

B0 to + 1

C+ 1 to 0

D+ 2 to + 1

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Question 12

jamb 2017

The alkyl group is represented by the general formula

AC_nH₂n

BC_nH₂n − 2

CC_nH₂n + 1

DC_nH₂n + 2

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Question 13

jamb 2017

The enzyme used in the hydrolysis of starch to dextrin and maltose is?

Alipase

Bamylase

Cinvertase

Dzymase

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Question 14

jamb 2017

The reaction of halogens with alkanes in the presence of sunlight is an example of

Aoxidation reaction

Baddition reaction

Chydrogenation reaction

Dsubstitution reaction

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Question 15

jamb 2017

Calculate the amount in moles of silver deposited when 9650C of electricty is passed through a solution of silver salt [= 96500 Cmol^-1]

A0.05

B10.80

C10.00

D0.10

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Question 16

jamb 2017

Tin is unaffected by air at ordinary temperature due to its?

ALow melting point

BWeak electropositive character

CHigh boiling point

DWhite lustrous appearance

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Question 17

jamb 2017

The mass of silver deposited when a current of 10A is passed through a solution of silver salt for 4830s is – (Ag = 108 F = 96500(mol-1)

A54.0g

B27.0g

C13.5g

D108.0g

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Question 18

jamb 2017

The shape of ammonia molecules is

Atrigonal pyramidal

Boctahedral

Csquare planar

Dtetrahedral

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Question 19

jamb 2017

\(^{226}_{88}Ra\) → \(^x_{86}Rn\) + alpha particle

A226

B220

C227

D222

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Question 20

jamb 2017

When ΔH is negative, a reaction is said to be

Aendothermic

Bexothermic

Creversible

Dionic

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Question 21

jamb 2017

The ideal gas laws and equations are true for all gases at

Alow pressures and lower temperatures

Blow temperatures and high pressures

Chigh pressures and high temperatures

Dlow pressure and high temperatures

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Question 22

jamb 2017

The salt formed from a weak acid and a strong base hydrolyzes in water to form

AA saturated solution

Ban acidic solution

Ca buffer solution

Dan alkaline solution

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Question 23

jamb 2017

Incomplete oxidation of ethanol yields

ACH₃COOH

BCH₃COCH₃

CCH₃CH₂OCH₂CH₃

DCH₃CHO

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Question 24

jamb 2017

A sample of orange juice is found to have a PH of 3.80. What is the concentration of the hydroxide ion in the juice?

A1.6 \(\times\) 10^-4

B6.3 \(\times\) 10^-11

C6.3 \(\times\) 10^-4

D1.6 \(\times\) 10^-11

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Question 25

jamb 2017

When few drops of concentrated trioxonitrate(V) acid is added to an unknown sample and wanned an intense yellow colouration is observed. The likely functional group present in the sample is

ANH₂RCHCOOH

BCHO

CCO

DCNH₂

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Question 26

jamb 2017

An isomer of C₅H₁₂ is

A2–ethyl butane

Bbutane

C2–methyl butane

D2–methyl propane

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Question 27

jamb 2017

The oxidation number of iodine in KIO₃ is

A+7

B+3

C+5

D+6

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Question 28

jamb 2017

A given mass of gas occupies 2dm³ at 300k. At what temperature will its volume be doubled, keeping the pressure constant?

A400k

B480k

C550k

D600k

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Question 29

jamb 2017

For a general equation of the nature xP + yQ → mR + nS, the expression for the equilibrium constant is

Ak [P]^x [Q]^y

B\(\frac{[P]^x [Q]^y}{[R]^m [S]^n}\)

C\(\frac{[R]^m [S]^n}{[P]^x [Q]^y}\)

D\(\frac{m[R] n[S]}{x[P] y[Q] }\)

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Question 30

jamb 2017

The constituent of air necessary in the rusting process are

AO₂ and H₂O

BAr and CO₂

CCO₂ and H₂O

DO₂ and CO₂

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