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 41:

  The electronic configuration of element Z is 1s${}^2$ 2s${}^2$ 2p${}^6$ 3s${}^2$ 3p${}^1$. What is the formula of the compound formed between Z and tetraoxosulphate (VI) ion.

  Options:
  A) Z${}_3$(SO${}_4$)${}_2$
  B) ZSO${}_4$
  C) Z${}_2$ SO${}_4$
  D) Z${}_2$(SO${}_4$)${}_3$
  Show Answer
  The correct answer is D .
• Question 42: Which of the following statement is false? Options:
  A) Acids react with some metals, liberating hydrogen
  B) Acids react with carbonates, liberating carbondioxide
  C) Acids conduct electricity and are decomposed by the current, liberating hydrogen at the anode
  D) Acids have a sour taste
  E) Acids change the colour of indicators
  Show Answer
  The correct answer is C .
• Question 43: What volume of oxygen will remain after reacting 8cm³ of hydrogen with 20cm³ of oxygen? Options:
  A) 10 cm³
  B) 12 cm³
  C) 14 cm³
  D) 16 cm³
  Show Answer
  The correct answer is D .
• Question 44: 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) CH₂O
  B) C₃H₆O₃
  C) C₆H₁₂O₆
  D) C₆H₁₂O₃
  Show Answer
  The correct answer is C .
• Question 45: Which of the following is a deliquescent compound? Options:
  A) Na₂CO₃
  B) CaCl₂
  C) CuO
  D) Na₂CO₃.10H₂O
  Show Answer
  The correct answer is B .
• Question 46:

  

  Use the option above to answer this question. The structure of benzoic acid is

  Options:
  A) A
  B) B
  C) C
  D) D
  Show Answer
  The correct answer is D .
• Question 47:

  

  Which of the curves above represents the behaviour of 1 mole of an ideal gas?

  Options:
  A) l
  B) ll
  C) lll
  D) lV
  Show Answer
  The correct answer is C .
• Question 48: In an electrolytic set-up to protect iron from corrosion, the iron is? Options:
  A) made cathode
  B) made anode
  C) used with a metal of lower electropositive potential
  D) initially coated with tin
  Show Answer
  The correct answer is D .
• Question 49:

  2Na_(s) + 2H₂O_(l) → 2NaOH_(aq) + H_2(g)

  From the equation above, calculate the mass of sodium hydroxide produced by 2.3g of sodium.

  [H = 1, O = 16, Na = 23]

  Options:
  A) 0.40g
  B) 0.80g
  C) 4.00g
  D) 8.00g
  Show Answer
  The correct answer is C .
• Question 50:

  What is eutrophication?

  Options:
  A) The release of harmful chemicals into water bodies
  B) The excessive growth of algae due to nutrient enrichment
  C) The presence of heavy metals in water
  D) The formation of oil slicks on water surfaces
  Show Answer
  The correct answer is B .