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 31: When stem is passed over red hot carbon the substances produced are Options:
  A) hydrogen and trioxocarbonate (IV) acid
  B) hydrogen, oxygen and carbon (IV) oxide
  C) hydrogen and carbon (ii) oxide
  D) hydrogen and carbon (IV) oxide
  Show Answer
  The correct answer is C .
• Question 32: The combustion of ethene, C ₂H ₄, is given by the equation C ₂H ₄ + 30 ₂ → 2CO₂ + 2H₂ O; ∆H = - 1428 KJ. If the molar heats of formation of water and carbon (IV) oxide are - 286 kJ and - 396 kJ respectively, calculate the molar heat of formation of ethene in KJ Options:
  A) - 2792
  B) + 2792
  C) - 64
  D) + 64
  Show Answer
  The correct answer is D .
• Question 33: If the elements X and Y have atomic numbers 11 and 17 respectively, what type of bond can they form? Options:
  A) Dative
  B) Covalent
  C) Lonic
  D) Metallic
  Show Answer
  The correct answer is C .
• Question 34: The principal constituent of natural gas is Options:
  A) methane
  B) ethane
  C) propane
  D) Butane
  Show Answer
  The correct answer is A .
• Question 35: The solution with the lowest pH value is Options:
  A) 5 ml of (m/10) HCL
  B) 10 ml of (m/10) HCL
  C) 15 ml of (m/5) HCL
  D) 20 ml of (m/8) HCL
  Show Answer
  The correct answer is A .
• Question 36: Geometric isomerism can exist in Options:
  A) hex-3-ene
  B) hexane
  C) prop-l-ene
  D) 3-methyl but -l-ene
  Show Answer
  The correct answer is A .
• Question 37: When glowing splint is inserted into the mouth of a jar containing a gas, the splint is extinguished. The gas gives a white precipitate when passing into barium hydroxide. The gas is? Options:
  A) methane
  B) hydrogen chloride
  C) hydrogen
  D) nitrogen
  E) carbondioxide
  Show Answer
  The correct answer is E .
• Question 38:

  Oxygen is absent in?

  Options:
  A) Kerosene
  B) Soil
  C) Glass
  D) Cement
  Show Answer
  The correct answer is A .
• Question 39: Sodium and potassium belong to the same group of the Periodic Table. This is because? Options:
  A) both are metals
  B) both are soft and lighter than water
  C) both form cations by losing electrons
  D) both have identical electronic configuration
  E) both react with water vigorously
  Show Answer
  The correct answer is D .
• Question 40: Calculate the number of moles of HCl present in 20cm³ of a 0.75M solution of the acid Options:
  A) 0.015 mole
  B) 0.038 mole
  C) 3.800 moles
  D) 1.500 moles
  Show Answer
  The correct answer is A .