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Chemistry Past Questions

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114 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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114 questions

Question 1 of 20 114 total questions

Question 31

jamb 2015

what is the pH of 0.00lmoldm³ solution of sodium hydroxide

A14

B13

C12

D11

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Question 32

jamb 2015

Which of the following compounds can be represented by the molecular formula C2 H6O?

Apropanal

Bethanol

Cmethanoic acid

Dglucose

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Question 33

jamb 2015

If glucose is heated with concentrated tetraoxosulphate(vi)acid, it will be dehydrated to?

Acarbon

Bcarbon(iv)oxide

Cethane

Dethanol

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Question 34

jamb 2015

The substance that is used in the steel industry for the removal of carbon. Sulphur and phosphorus impurities from pig iron is

Aoxygen

Bchlorine

Cnitrogen

Dhydrogen

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Question 35

jamb 2015

In countries where the temperature fall below 273k, salt always spilled on the road in order to

Aincrease the boiling point

Bincrease the density of the ice

Cmake the ice impure

Dreduce the freezing point of ice

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Question 36

jamb 2015

Alloys are best prepared by

Aelectroplating

BArc-welding

Creducing and mixture of their metallic

Dcooking a molten of the metals

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Question 37

jamb 2015

Electronic configuration of an element 13 in the subsidiary energy level is

A\( 1s^2 2s^2 2p^6 3s^2 3p^1 \)

B\( 1s^22s^2 2p^4 3p^1 3s^1 \)

C\( 1s^2 2s^2 2p^6 3s^2 3p^3 \)

D\( 1s^1 2s^2 2p^6 3s^2 3p^4 \)

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Question 38

jamb 2015

Which of the following gives a precipitation when treated with NaOH Solution?

AAlCl₃

BNH₄Cl

CNa₂CO₃

DCH₃COONa

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Question 39

jamb 2015

PCL5(g)= PCL3(g) + Cl2(g)

In the reaction above, a decrease in pressure will

ADecelerate the reaction

BIncrease yield of Pcl3

CIncrease the yield of Pcl5

DAccurate the reaction

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Question 40

jamb 2015

According to the kinetic theory an absence in temperature causes the kinetic energy of particles to

Adecrease

Bincrease

Cremain constant

Dbe zero

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Question 41

jamb 2015

A difference between chemical and physical change is that in a chemical change

Aoxygen is consumed

Bheat is supplied

Cthe reversible process occurs

Da new substance is formed

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Question 42

jamb 2015

The furring of kettles is caused by the presence of what compound in water?

Acalcium tetraoxosulphate (IV)

Bcalcium hydrogentrioxocarbonate (IV)

Ccalcium hydroxide

Dcalcium trioxocarbonate (IV)

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Question 43

jamb 2015

Which of the following results in the fall of acid rain?

Aoxide of lead

Bparticulate matter

Coxides of sulphur

Dgaseous hydrocarbon

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Question 44

jamb 2015

Detergents are manufactured with straight hydrocarbon chains, is to make them

Asoluble

Bbiodegradable

Ccheaper

Dfoamy

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Question 45

jamb 2015

NH_3(g) + HCl_(s) → NH ₄Cl _(s)

The entropy change in the system above is

Apositive

Bzero

Cnegative

Dintermediate

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Question 46

jamb 2015

When sugar is dissolve in tea, the reaction is accomplished by?

Apositive change

Bnegative entropy change

Cno entropy change

Da minimum entropy change

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Question 47

jamb 2015

The elements that belong to the third period of periodic table are

ALi, Be, Al and D

BNa, P, O and Cl

CB, C, N, and O

DNa, Mg, S and Ar

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Question 48

jamb 2015

An oxidation state of Cr in K2Cr2O7

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Question 49

jamb 2015

A compound contains 40.0% carbon, 6.7% hydrogen and 53.3% oxygen. If the molar mass of the compound is 180, Find the molecular formula [H = 1, C = 12, O = 16)

ACH₂O

BC₃H₆O₃

CC₆H₁₂O₆

DC₆H₁₂O₃

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Question 50

jamb 2015

What volume of 0.5mldm³ H₂SO₄ will exactly neutralize 20cm³ of 0.1moldm³ NaOH Solution?

A2.0cm³

B5.0cm³

C6.8cm³

D8.3cm³

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