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 81: Two elements, P and Q with atomic numbers 11 and 8 respectively , combine chemically to form the compound P_xQ_Y. The respective values of x and y are? Options:
  A) 1 and 1
  B) 1 and 2
  C) 2 and 1
  D) 3 and 1
  Show Answer
  The correct answer is C .
• Question 82: Which of the additives could improve the quality of steel? Options:
  A) Silicon
  B) Sulphur and phosphorus
  C) Carbon
  D) Chromium and nickel
  Show Answer
  The correct answer is D .
• Question 83:

  

  The functional group represented in the compound above is

  Options:
  A) alkanol
  B) alanal
  C) alkanone
  D) alanoate
  Show Answer
  The correct answer is C .
• Question 84: What are the possible oxidation numbers of an element if its atomic number is 17? Options:
  A) -1 and 7
  B) -1 and 6
  C) -3 and 5
  D) -2 and 6
  Show Answer
  The correct answer is A .
• Question 85:

  CH_4(g) + Cl_2(g) → CH₃ Cl_(s) + HCl_(g)

  The major factor that influence the rate of the reaction above is

  Options:
  A) catalyst
  B) temperature
  C) concentration
  D) light
  Show Answer
  The correct answer is D .
• Question 86: How many moles of oxygen molecules would be produced from the decomposition of 2.50 moles of potassium trioxochlorate (V)? Options:
  A) 2.50
  B) 3.50
  C) 3.75
  D) 7.50
  Show Answer
  The correct answer is C .
• Question 87:

  

  The function of the copper (ll)tetraoxosulphate (IV) in dilute H₂SO₄ in the figure above is to

  Options:
  A) dry the gas
  B) absorb phosphine impurity
  C) absorb ethene impurity
  D) from an acetylide with ethyne
  Show Answer
  The correct answer is B .
• Question 88:

  Which of the following statements is true?

  Options:
  A) Metals conduct electricity while non-metals do not
  B) Metals have high density, non-metals have low density
  C) Metals form basic oxides, non-metals form acidic oxides
  D) In the electro chemical series, metals are above hydrogen while non-metals are below hydrogen
  E) Metals lose elections while non-metals gain electron during normal reactions
  Show Answer
  The correct answer is E .
• Question 89: Alloys are best prepared by Options:
  A) electroplating
  B) Arc-welding
  C) reducing and mixture of their metallic
  D) cooking a molten of the metals
  Show Answer
  The correct answer is D .
• Question 90:

  The alkanoic acid found in human sweat is

  Options:
  A) CH${}_3$-COOH
  B) CH${}_3$—CH${}_2$—COOH
  C) H-COOH
  D) CH${}_3$
  Show Answer
  The correct answer is B .