Chemistry WAEC Past Questions
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Chemistry WAEC Past Questions 2024 [OBJECTIVE]

Chemistry WAEC past questions is now here for you to aid you with your studies. Past questions are very important for students who are preparing to write their exams as they can use it to test their knowledge and see if all they have heard is entering their head.

Another good thing about past questions is that it can also help you know if you have covered the full syllabus oor have things that have not been covered. Without waste of time, let’s get started

Chemistry WAEC Past Questions 2024

Below are the complete questions that you might likely see on your next Chemistry WAEC examination.

1. The vapour density of an organic compound with the molecular formula C2H4O2𝐶2𝐻4𝑂2, is

[H=1.0, C=12.0, O= 16.0]

  • A. 40
  • B. 120
  • C. 65
  • D. 30
2. The following statements are correct except
  • A. energy is released when liquids change to solids.
  • B. carbon atoms in gaseous methane are further apart than those in solid diamond.
  • C. there is large decrease in the volume of a solid metal when pressure is applied to it.
  • D. particles move faster in the gaseous state than in the liquid state.
3. Which of the following reactions represents the hydrolysis of an alkanoate?
  • A. CH3COOH+OHH+CH3COO+H2O𝐶𝐻3𝐶𝑂𝑂𝐻+𝑂𝐻−⇌𝐻+⇌𝐶𝐻3𝐶𝑂𝑂−+𝐻2𝑂
  • B. CH3COOH+C2H5OHH+CH3COOC2H5+H2O𝐶𝐻3𝐶𝑂𝑂𝐻+𝐶2𝐻5𝑂𝐻⇌𝐻+⇌𝐶𝐻3𝐶𝑂𝑂𝐶2𝐻5+𝐻2𝑂
  • C. CH3COOC2H5+H2OH+CH3COO+CH3CH2OH𝐶𝐻3𝐶𝑂𝑂𝐶2𝐻5+𝐻2𝑂⇌𝐻+⇌𝐶𝐻3𝐶𝑂𝑂−+𝐶𝐻3𝐶𝐻2𝑂𝐻
  • D.  CH3COOCH2CH3+H2OH+CH3COOH+CH3CH2OH𝐶𝐻3𝐶𝑂𝑂𝐶𝐻2𝐶𝐻3+𝐻2𝑂⇌𝐻+⇌𝐶𝐻3𝐶𝑂𝑂𝐻+𝐶𝐻3𝐶𝐻2𝑂𝐻

4. The following steps are scientific methods except

  • A. experimentation
  • B. problem identification
  • C. Analysis
  • D. Open-mindedness
5. Alkenes can be manufactured by
  • A. the combustion of alkanes.
  • B. the cracking of hydrocarbons.
  • C. polymerization reactions.
  • D. addition of hydrogen to unsaturated vegetable oils.
6. The formation of a bond between hydrogen and a highly electronegative atom results in
  • A. polarity
  • B. electrovalent bond.
  • C. dipole
  • D. metallic bond
7. Which of the elements in the table below would react more readily with chlorine?  
Element Ionization energy (KJ mol1×103𝑚𝑜𝑙−1×10−3)
W 12.0
X 21.0
Y 106.0
Z 200.0

 

  • A. Y and Z only
  • B. X and Z only
  • C. W and X only
  • D. W and Z only
8. Which of the following properties does not give evidence of the kinetic theory of matter?
  • A. Diffusion
  • B. Melting
  • C. Polymerization
  • D. Evaporation
9. Dilute trioxonitrate (V) acid does not produce hydrogen when it reacts with metals because
  • A. it reacts with the product.
  • B. it is highly corrosive.
  • C. there is no visible reaction.
  • D. it is a strong oxidizing agent.
10. Which of the following statements is correct?
  • A. Addition reactions occur between alkanes and chlorine.
  • B. Butane has a lower boiling point than propane.
  • C. Pentane has five isomers.
  • D. An alkane with 49 carbon atoms contains 100 hydrogen atoms
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11. A mixture containing two salts of different solubility can be separated by
  • A. chromatography.
  • B. crystallization.
  • C. distillation.
  • D. evaporation.
12. Species that occur in a reaction pathway but not in the overall reaction are known as
  • A. Reactants
  • B. Inhibitors
  • C. Products
  • D. Intermediates
13. How many moles are there in 3.0 g of O2𝑂2? [O = 16.0]
  • A. 0.0093 moles.
  • B. 0.0930 moles.
  • C. 0.0625 moles.
  • D. 0.6250 moles.
14. Which of the following equimolar solutions has the highest conductivity?
  • A. H2SO4(aq)𝐻2𝑆𝑂4(𝑎𝑞)
  • B. NaOH(aq)𝑁𝑎𝑂𝐻(𝑎𝑞)
  • C. H2CO3(aq)𝐻2𝐶𝑂3(𝑎𝑞)
  • D. CH3COONH4(aq)𝐶𝐻3𝐶𝑂𝑂𝐻4(𝑎𝑞)
15. The pair of compounds that belongs to the same homologous series is
  • A. C2H6𝐶2𝐻6 and C4H10𝐶4𝐻10
  • B. C3H8𝐶3𝐻8 and C3H6𝐶3𝐻6
  • C. C2H4𝐶2𝐻4 and C4H10𝐶4𝐻10
  • D. C4H10𝐶4𝐻10 and C5H10

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16. Which of the following equations does not illustrate correctly one of the reactions of chlorine?
  • A. Ca(OH)2+Cl2CaOCl2+H2O𝐶𝑎(𝑂𝐻)2+𝐶𝑙2→𝐶𝑎𝑂𝐶𝑙2+𝐻2𝑂
  • B. Cl2+2NaF2NaCl+F2𝐶𝑙2+2𝑁𝑎𝐹→2𝑁𝑎𝐶𝑙+𝐹2
  • C. Cl2+2NaOHNaCl+NaClO+H2O𝐶𝑙2+2𝑁𝑎𝑂𝐻→𝑁𝑎𝐶𝑙+𝑁𝑎𝐶𝑙𝑂+𝐻2𝑂
  • D. H2S+Cl22HCl+S𝐻2𝑆+𝐶𝑙2→2𝐻𝐶𝑙+𝑆
17. The salt solution formed firm a reaction between ethanoic acid and sodium hydroxide solution would be
  • A. amphoteric.
  • B. neutral
  • C. basic
  • D. acidic
18. The separation technique that is suitable for separating iodine from tetrachloromethane is
  • A. solvent extraction
  • B. decantation
  • C. fractional distillation
  • D. filtration
19. Consider the following reaction equation:

2SO3(g)2SO2(g)+O22𝑆𝑂3(𝑔)→2𝑆𝑂2(𝑔)+𝑂2(g)
∆H = +198 kJ/mol
Which of the following statements about the reaction is correct?

  • A. 198 kJ of energy is given off
  • B. The reaction is exothermic
  • C. The reaction container would feel warm.
  • D. 198 kJ of energy is absorbed
20. Arrange the following compounds in decreasing order of their boiling points: NH3𝑁𝐻3, HF, SiH4𝑆𝑖𝐻4CH4𝐶𝐻4
  • A. HF,NH3𝑁𝐻3SiH4𝑆𝑖𝐻4CH4𝐶𝐻4
  • B. CH4𝐶𝐻4SiH4𝑆𝑖𝐻4, HF, NH3𝑁𝐻3,
  • C. NH3𝑁𝐻3,CH4𝐶𝐻4SiH4𝑆𝑖𝐻4, HF
  • D. CH4𝐶𝐻4SiH4𝑆𝑖𝐻4NH3𝑁𝐻3, HF

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21. Copper (II) ions are able to participate in co-ordinate covalent bonding because they
  • A. are coloured
  • B. are positively charged
  • C. have vacant d-orbital
  • D. have unpaired electrons
22. What takes place at the cathode during electrolysis?
  • A. Anions lose electrons
  • B. Anions are oxidized
  • C. Cations are oxidized
  • D. Cations are discharged.
23. Carbon is deposited in the exhaust pipes of cars because of
  • A. presence of additives in petrol
  • B. incomplete combustion of petrol
  • C. presence of carbon in petrol
  • D. contamination of petrol with diesel
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24. Which of the following laws or theory cannot be explained by the application of the kinetic theory of gases?
  • A. Dalton’s atomic theory
  • B. Charle’s law
  • C. Boyle’s law
  • D. Gay- Lussac’s law
25. How many unpaired electrons are present in 26Fe3+26𝐹𝑒3+?
  • A. 4
  • B. 2
  • C. 3
  • D. 5

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26. A consequence of global warming is
  • A. air pollution
  • B. High Humidity
  • C. flooding
  • D. Water pollution
27. Going down group II in the periodic table normally
  • A. ionization energy increases
  • B. melting point increases
  • C. shielding effect decreases
  • D. electronegativity increases
28. The primary component of natural gas
  • A. ethane
  • B. methane
  • C. butane
  • D. propane
29. The gas that is less dense than air is
  • A. nitrogen
  • B. chlorine
  • C. Carbon(IV) oxide
  • D. Oxygen
30. The periodic property that is used to determine whether a covalent molecule is polar or not is
  • A. atomic radius
  • B. ionization energy
  • C. electron affinity
  • D. electronegativity

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31. If 10031003 of a saturated solution of sodium tetraoxosulphate (VI) at 30° C contains 10.5 g of the salt, what would be its solubility at this temperature? [(Na2SO4𝑁𝑎2𝑆𝑂4 = 142]
  • A. 2.15 mol dm-3
  • B. 0.74 mol dm-3
  • C. 0.60 mol dm-3
  • D. 0.57 mol dm-3
32. A compound that could be dried by using conc. tetraoxosulphate (VI) acid and not by calcium oxide is likely to be
  • A. a deliquescent salt
  • B. a neutral salt
  • C. an alkaline gas
  • D. an acid anhydride
33. Which of the statements about gases is not correct?
  • A. Gases have low densities compared to solids and liquids of equal mass.
  • B. The total kinetic energy of the gas is not affected by collision
  • C. Molecules of the gas are in constant motion
  • D. Gases are highly soluble in water at high temperatures
34. Determine the volume of 0.100 mol of HCl in 0.250moldm30.250𝑚𝑜𝑙𝑑𝑚3 of solution.
  • A. 200cm3200𝑐𝑚3
  • B. 100cm3100𝑐𝑚3
  • C. 20cm320𝑐𝑚3
  • D. 400cm3400𝑐𝑚3
35. Positive ions in a sea of electrons are found in
  • A. covalent bonds
  • B. metallic bonds
  • C. dative bonds
  • D. ionic bonds
36. An element X has two isotopes, 65X3065𝑋30 and 66X3066𝑋30 with relative abundance of 60 % and 40% respectively. The relative atomic mass of X is
  • A. 66.00
  • B. 65.50
  • C. 65.00
  • D. 65.40
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37. Which of the following statements about the collision theory is correct?
  • A. Ineffective collision brings about chemical reaction
  • B. All collisions bring about reactions
  • C. The rate of reaction is proportional to the number of effective collisions
  • D. Collision of molecules will split the molecules to react
38. Which of the following elements has its valence electrons in the s-orbital?
  • A. Aluminum
  • B. Phosphorus
  • C. Sodium
  • D. Carbon
39. Petrochemistry is an example of
  • A. applied chemistry
  • B. Biochemistry
  • C. Pure chemistry
  • D. Environmental chemistry
40. The molecule that has a nonpolar covalent bond is
  • A. HCl
  • B. NH3𝑁𝐻3
  • C. Cl2𝐶𝑙2
  • D. H2O
41. The reduction half equation of the following reaction is:

Zn(s)+CuSO4(aq)ZnSO4(aq)+Cu(s)𝑍𝑛(𝑠)+𝐶𝑢𝑆𝑂4(𝑎𝑞)→𝑍𝑛𝑆𝑂4(𝑎𝑞)+𝐶𝑢(𝑠)

  • A. Zn(s)Zn2+(aq)+2e𝑍𝑛(𝑠)→𝑍𝑛(𝑎𝑞)2++2𝑒−
  • B. CuSO4(s)+H2O(l)𝐶𝑢𝑆𝑂4(𝑠)+𝐻2𝑂(𝑙) → Cu2+(aq)𝐶𝑢(𝑎𝑞)2+ + SO24(aq)𝑆𝑂4(𝑎𝑞)2−
  • C. Cu2+(aq)+2eCu(s)𝐶𝑢(𝑎𝑞)2++2𝑒−→𝐶𝑢(𝑠)
  • D. Cu2+(aq)+eCu(s)𝐶𝑢(𝑎𝑞)2++𝑒−→𝐶𝑢(𝑠)
42. Why are H2SO4𝐻2𝑆𝑂4 and CaCl2𝐶𝑎𝐶𝑙2, not suitable for drying ammonia gas? They
  • A. are poisonous.
  • B. pollute the gas
  • C. are corrosive
  • D. react with the gas
43. Isoelectronic species have the same number of
  • A. ions
  • B. electrons
  • C. protons
  • D. neutrons
44. Which of the following gases has the lowest rate of diffusion?

[H=1.0, C=12.0, N = 14.0, O= 16.0]

  • A. Nitrogen
  • B. methane
  • C. Ammonia
  • D. Oxygen
45. An example of a crystalline substance that does not possess water of crystallization is
  • A. potassium trioxonitrate (V)
  • B. sodium tetraoxosulphate (VI).
  • C. iron (II) tetraoxosulphate (VI)
  • D. sodium trioxocarbonate (IV).
46. The best indicator to use for the titration of ethanoic acid with sodium hydroxide is
  • A. methyl orange
  • B. phenolphthalein
  • C. screened methyl orange
  • D. methyl red
47. The relative molar mass of a gaseous hydrocarbon is 30. Determine its vapour density.
  • A. 45
  • B. 30
  • C. 15
  • D. 60
48. Thermal cracking of alkanes usually
  • A. is an exothermic process
  • B. produces only small alkanes
  • C. involves decomposition
  • D. requires hydrogen
49. How many grammes of NaOH(s) would be needed to produce 100.0 cm3 of a 0.20 mol dm-3 NaOH, (aq)? [NaOH = 40.0]
  • A. 800.0g
  • B. 0.02 g
  • C. 20.0 g
  • D. 0.80 g
50. How many moles of copper would be deposited by passing 1 Faraday of electricity through a CuCl2𝐶𝑢𝐶𝑙2 solution?
  • A. 2 moles
  • B. 0.5moles
  • C. 0.025moles
  • D. 1 mole

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