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.

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

88 questions
Question 1 of 20 88 total questions
Question 21
jamb 2023

When a substance is oxidized, it

ALoses electrons
BGains oxygen atoms
CGains electrons
DLoses protons (H+ ions)
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Question 22
jamb 2023

What is the symbol used to represent an alpha particle?

Aα
Bγ
Cδ
Dβ
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Question 23
jamb 2023

Which of the following is a common property of non-metals?

AExist as solids at room temperature
BTend to gain electrons in chemical reactions
CHigh thermal conductivity
DReadily form cations in chemical reactions
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Question 24
jamb 2023

What is the mass percentage of carbon (C) in methane (CH4)? (The molar mass of carbon is approximately 12 g/mol.)

A25%
B12%
C75%
D50%
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Question 25
jamb 2023

What type of reaction is involved in the formation of alkanols from alkenes?

AElimination reaction
BRedox reaction
CSubstitution reaction
DAddition reaction
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Question 26
jamb 2023

What is the common name for ethanoic acid?

AAcetic acid
BButyric acid
CPropionic acid
DFormic acid
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Question 27
jamb 2023

Which separation technique is used to separate different pigments in a mixture based on their affinity for a stationary phase and a mobile phase?

AChromatography
BFiltration
CDecantation
DDistillation
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Question 28
jamb 2023

What is the empirical formula of a compound containing 40.00% carbon, 6.67% hydrogen, and 53.33% oxygen by mass?

AC\(_4\)H\(_8\)O\(_4\)
BCH\(_2\)O
CC\(_2\)H\(_4\)O\(_2\)
DC\(_3\)H\(_6\)O\(_3\)
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Question 29
jamb 2023

What is the main source of carbon monoxide (CO) in urban areas?

AVolcanic eruptions
BVehicle emissions
CForest fires
DIndustrial processes
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Question 30
jamb 2023

Which of the following is a primary constituent of crude oil?

APentane
BEthanol
CHeptane
DMethane
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Question 31
jamb 2023

Which group does calcium belong to in the periodic table?

AAlkaline earth metals
BHalogens
CAlkali metals
DNoble gases
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Question 32
jamb 2023

What is the principal ore of iron, from which iron is extracted?

ACalcite
BBauxite
CMagnetite
DHematite
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Question 33
jamb 2023

How many pi (\(\pi\)) bonds are there in an alkene with six carbon atoms?

A1
B6
C5
D3
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Question 34
jamb 2023

What is the chemical formula of rust, which is formed on the surface of iron in the presence of oxygen and moisture?

AFe\(_3\)O\(_4\)
BFeO
CFe(OH)3
DFe\(_2\)O\(_3\)
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Question 35
jamb 2023

What is the molar mass of water (H2O)?

A18 g/mol
B22 g/mol
C16 g/mol
D12 g/mol
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Question 36
jamb 2023

Which organic compound is responsible for the characteristic aroma of fruits?

AAlkane
BAlkyne
CEster
DAmine
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Question 37
jamb 2023

Which of the following factors does NOT affect the rate of a chemical reaction?

AConcentration of reactants
BPresence of a catalyst
CMolecular weight of products
DTemperature
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Question 38
jamb 2023

When an acidic solution is diluted, what happens to its pH?

AIt depends on the specific acid
BIt decreases
CIt remains the same
DIt increases
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Question 39
jamb 2023

What is the product of the electrolysis of aqueous sodium chloride (NaCl) using inert electrodes?

AHydrogen gas at the cathode and chlorine gas at the anode
BHydrogen gas at the cathode and oxygen gas at the anode
CSodium metal at the cathode and chlorine gas at the anode
DSodium metal at the cathode and oxygen gas at the anode
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Question 40
jamb 2023

Which of the following alkanes has a straight-chain structure?

ACyclopentane (C5H10)
BIsobutane (C4H10)
C2 - methyl propane (C4H10)
DPentane (C5H12)
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