Chemistry WAEC Past Questions 2024 [OBJECTIVE]

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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

C_{2} H_{4} O_{2}

, 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. $C H_{3} C O O H + O H^{-} ⇌ H^{+} ⇌ C H_{3} C O O^{-} + H_{2} O$
B. $C H_{3} C O O H + C_{2} H_{5} O H ⇌ H^{+} ⇌ C H_{3} C O O C_{2} H_{5} + H_{2} O$
C. $C H_{3} C O O C_{2} H_{5} + H_{2} O ⇌ H^{+} ⇌ C H_{3} C O O^{-} + C H_{3} C H_{2} O H$

D. $C H_{3} C O O C H_{2} C H_{3} + H_{2} O ⇌ H^{+} ⇌ C H_{3} C O O H + C H_{3} C H_{2} O H$

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 $m o l^{- 1} \times 10^{- 3}$ )
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

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

O_{2}

? [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. $H_{2} S O_{4} (a q)$
B. $N a O H_{(} a q)$
C. $H_{2} C O_{3} (a q)$
D. CH3COONH4 $C H_{3} C O O H_{4} (a q)$

15. The pair of compounds that belongs to the same homologous series is

A. $C_{2} H_{6}$ and $C_{4} H_{10}$
B. $C_{3} H_{8}$ and $C_{3} H_{6}$
C. $C_{2} H_{4}$ and $C_{4} H_{10}$
D. $C_{4} H_{10}$ and $C_{5} H_{10}$

16. Which of the following equations does not illustrate correctly one of the reactions of chlorine?

A. $C a (O H)_{2} + C l_{2} \to C a O C l_{2} + H_{2} O$
B. $C l_{2} + 2 N a F \to 2 N a C l + F_{2}$
C. $C l_{2} + 2 N a O H \to N a C l + N a C l O + H_{2} O$
D. $H_{2} S + C l_{2} \to 2 H C l + S$

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:

$2 S O_{3} (g) \to 2 S O_{2} (g) + O_{2}$ (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:

N H_{3}

, HF,

S i H_{4}

C H_{4}

A. HF, $N H_{3}$ , $S i H_{4}$ , $C H_{4}$
B. $C H_{4}$ , $S i H_{4}$ , HF, $N H_{3}$ ,
C. $N H_{3}$ , $C H_{4}$ , $S i H_{4}$ , HF
D. $C H_{4}$ , $S i H_{4}$ , $N H_{3}$ , HF

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

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

_{26} F e^{3 +}

A. 4
B. 2
C. 3
D. 5

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

31. If

100^{3}

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? [(

N a_{2} S O_{4}

= 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

0.250 m o l d m^{3}

of solution.

A. $200 c m^{3}$
B. $100 c m^{3}$
C. $20 c m^{3}$
D. $400 c m^{3}$

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,

^{65} X_{30}

and

^{66} X_{30}

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

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. $N H_{3}$
C. $C l_{2}$
D. $H_{2} O$

41. The reduction half equation of the following reaction is:

$Z n_{(s)} + C u S O_{4 (a q)} \to Z n S O_{4 (a q)} + C u_{(s)}$

A. $Z n_{(s)} \to Z n_{(a q)}^{2 +} + 2 e^{-}$
B. $C u S O_{4 (s)} + H_{2} O_{(l)}$ → $C u_{(a q)}^{2 +}$ + $S O_{4 (a q)}^{2 -}$
C. $C u_{(a q)}^{2 +} + 2 e^{-} \to C u_{(s)}$
D. $C u_{(a q)}^{2 +} + e^{-} \to C u_{(s)}$

42. Why are

H_{2} S O_{4}

and

C a C l_{2}

, 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

C u C l_{2}

solution?

A. 2 moles
B. 0.5moles
C. 0.025moles
D. 1 mole

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Chemistry WAEC Past Questions 2024 [OBJECTIVE]

Chemistry WAEC Past Questions 2024

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Chemistry WAEC Past Questions 2024

Frequently Asked Questions

Is Chemistry hard?

How do i prepare for WAEC?

Conclusion

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