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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 1981

28.8 cm³ of nitrogen at 15°C is cooled to O°C at constant pressure, the new volume of nitrogen is?

A17.4 cm³

B14.7 cm³

C27.3 cm³

D31.7 cm³

View Explanation & Discuss

Question 12

jamb 1981

Which of the following statements about phosphorus is NOT correct?

APhosphorus is a solid mineral

BPhosphorus is obtained by oxidation reaction of phosphate

CPhosphorus exists in two allotropic forms

DBoth forms of phosphorus are interconvertible

EYellow phosporus ignites when rubbed on a rough surface

View Explanation & Discuss

Question 13

jamb 1981

Fats and oils are?

Aaddition products of long chain fatty acids and alkali

Baddition products of long-chain fattyy acids and glycerol

Ccondensation products of long-chain fatty acids and glycerol

Dcondensation products of formaldehyde and glycerol

Eliquids at 20°C

View Explanation & Discuss

Question 14

jamb 1981

When air is compressed?

Aits density decreases

Bit solidifies

Cits temperature decreases

Dits temperature increases

Eits temperature remains unchanged

View Explanation & Discuss

Question 15

jamb 1981

If an organic compound decolorizes bromine water then the compound is?

Asaturated

Bsupersaturated

Cunsaturated

Da solid

Eprotonated

View Explanation & Discuss

Question 16

jamb 1981

When sodium nitrate dissolves in water, ∆H is positive. This means that?

Athe reaction is catalysed

Bthe reaction is complete

Cthe reaction is exothermic

Dthe reaction is endthermic

Esodium nitrate is highly soluble in water

View Explanation & Discuss

Question 17

jamb 1981

Na₂CO₃ + 2HCI → 2NaCI + H₂O + CO₂. Using the above equation, what volume of carbondioxide, measured at s.t.p is liberated when 53g of sodium carbonate is dissolved in hydrochloric acid?
(1 mole of gas occupies 22.4 dm³ at s.t.p)
(Na = 23, C = 12, O = 16)

A44.8 dm³

B11.2 dm³

C100.1 dm³

D3.0 dm³

E22.4 dm³

View Explanation & Discuss

Question 18

jamb 1981

In the reaction of oxygen with hydrogen to produce water, which of the following statements is true?

AOne atom of hydrogen reacts with two atoms of oxygen to give one molecule of water

BTwo atoms of hydrogen react with two atoms of oxygen to give two molecules of water

COne molecule of oxygen reacts with one molecule of hydrogen to give two molecules of water

DOne molecule of hydrogen reaccts with two molecules of oxygen to give three molecules of water

EOne molecule of oxygen reacts with two molecules of hydrogen to give two molecules of water

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Question 19

jamb 1981

Which of the following is the electronic configuration of sodium?
(Atomic number of Na = 11)

A1s² 2s²2p⁶ 3s²

B1s² 2s²2p⁶ 3s² 3p1s² 2s²2p⁶ 3s¹

C1s² 2s²2p⁶ 3s¹

D1s² 2s²2p⁶ 3s^°

E1s² 2s²2p⁶ 4s¹

View Explanation & Discuss

Question 20

jamb 1981

A polymerization reaction is one in which?

Asmall molecules form giant molecules

Batoms form molecules

Cgiant molecules form small molecules

Dmolecules form volatile compounds

Ea molecule rearranges itself

View Explanation & Discuss

Question 21

jamb 1981

Allotropes are elements having?

Adifferent physical but the same chemical properties

Bdifferent chemical but the same physical properties

Cthe same chemical and physical properties

Ddifferent atomic structure

Ethe same position in the periodic table

View Explanation & Discuss

Question 22

jamb 1981

Which of the following can have an isomer?

AC₂H₄

BC₄H₁₀

CC₃H₈

DC₂H₆

EC₆H₆

View Explanation & Discuss

Question 23

jamb 1981

In the preparation of ammonia, which of the following is used as the drying agent?

ACaO

BCaCI₂

CConc. H₂SO₄

DP₂O₅

EH₃PO₄

View Explanation & Discuss

Question 24

jamb 1981

Which of the following processes takes place during electrolysis?

APositive ions are discharged at the anode bby gaining sufficient electrons to become neutral

BNegative ions are dicharged at the anode by gaining suficient electrons to become neutral

CPositive ions are discharged at the anode by losing sufficient electrons to become neutral

DNegative ions are discharge at the anode by losing sufficient electrons to become neutral

ENothing happens

View Explanation & Discuss

Question 25

jamb 1981

The brown coloration in nitric acid prepared in the laboratory can be removed by?

Aheating the acid

Bbubbling air through the acid

Ccooling the acid

Dadding a decolorizing agent

Eadding a base

View Explanation & Discuss

Question 26

jamb 1981

In the reaction
C + 2HNO₃ → CO₂ + NO₂ + NO + H₂O nitric acid is acting as?

Aa reducing agent

Ba nitrating agent

Can oxidizing agent

Da catalytic agent

Ea neutralizing agent

View Explanation & Discuss

Question 27

jamb 1981

If concentrated sulphric acid is added to sugar and warmed gently, the sugar changes from white to brown and finally to a black mas of carbon. In this reaction, concentrated sulphuric acid is acting as ?

Aa drying agent

Ban oxidizing agent

Ca dehydrated agent

Da reducing agent

Ea hydrolysing agent

View Explanation & Discuss

Question 28

jamb 1981

Which of the following statements is NOT true of electrovalent compounds?

AThey are solids

BThey do not vaporized easily

CThey usually dissolve in water

DThe elements forming the compounds normally have their valency electrons in a shared state

EThey conduct electricity

View Explanation & Discuss

Question 29

jamb 1981

the number of atoms in one mole of a substance is equal to?

Athe atomic number

Bthe avogadro number

Cthe gas constant

Dthe number of neutrons

Ethe number of electrons

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Question 30

jamb 1981

Oxidation is the process of?

Again of electrons

Bloss of electrons

Cgain of hydrogen

Dloss of oxygen

Eaddition of an electropositive element to a substance

View Explanation & Discuss

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