Chemistry Exam Past Questions and Answers | JAMB, WAEC and NECO

Chemistry is the study of the substances that make up matter. It looks at their properties, how they react with each other, and how these reactions can create new substances.

• Question 21:

  If 10.5g of lead (II) trioxonitrate (V) is dissolved in 20cm³ of distilled water at 18^oC, the solubility of the solute in mol dm^-3 is

  [Pb = 207, N = 14, O = 16]

  Options:
  A) 1.60
  B) 5.25
  C) 16.00
  D) 525.00
  Show Answer
  The correct answer is A .
• Question 22: The ability of carbon to form long chains is referred to as Options:
  A) alkylation
  B) acylation
  C) catenation
  D) carbonation
  Show Answer
  The correct answer is C .
• Question 23: The impurities formed during the laboratory preparation of chlorine gas are removed by Options:
  A) H₂O
  B) NH₃
  C) H₂SO₄
  D) HCl
  Show Answer
  The correct answer is A .
• Question 24: Which of the following properties is NOT peculiar to matter? Options:
  A) kinetic energy of particles increase from solid to gas
  B) Random motion of particles increases from liquid to gas
  C) Orderliness of particles increases from gas to liquid
  D) Random motion of particles increases from gas to solid
  Show Answer
  The correct answer is D .
• Question 25: Equal moles of ethyne and hydrogen iodide react to give Options:
  A) CH₂ = CH₂
  B) CH₂ - CHI
  C) CH₃ - CI
  D) CH₂ = CHI
  Show Answer
  The correct answer is D .
• Question 26: One of the major uses of alkane is Options:
  A) as domestic and industrial fuel
  B) in the hydrogenation of oils
  C) in the textile industries
  D) in the production of plastics
  Show Answer
  The correct answer is A .
• Question 27:

  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]

  Options:
  A) C${}_3$H${}_6$O${}_3$
  B) C${}_6$H${}_6$O${}_3$
  C) C${}_6$H${}_{12}$O${}_6$
  D) CH${}_2$O
  Show Answer
  The correct answer is C .
• Question 28:

  The shapes of water, ammonia, carbon (iv) oxide and methane are respectively

  Options:
  A) linear, tetrahedral, angular and pyramidal
  B) angular, pyramidal, linear and tetrahedral
  C) pyramidal, linear, tetrahedral and angular
  D) tetrahedral, angular, pyramidal and linear
  Show Answer
  The correct answer is B .
• Question 29:

  If gas A has a molar mass of 32 g/mol and gas B has a molar mass of 64 g/mol, what is the ratio of their diffusion rates?

  Options:
  A) 2:1
  B) 1:2
  C) 1:1
  D) 1:4
  Show Answer
  The correct answer is A .
• Question 30: The electronic configuration of elements X and Y are X = 2, 8, 6; Y = 2, 8, 7. The bond in the compound formed by X and Y is expected to be? Options:
  A) ionic
  B) covalent
  C) dative covalent
  D) metallic
  E) none of the above
  Show Answer
  The correct answer is B .