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 61: The processes which return carbon (IV) oxide to the atmosphere include Options:
  A) respiration, decay and combustion
  B) photosynthesis, respiration and transpiration
  C) ozone depletion, combustion and decay
  D) photosynthesis, decay and respiration
  Show Answer
  The correct answer is A .
• Question 62: What is the partial pressure of hydrogen gas collected over water at standard atmospheric pressure and 25^oC if the saturation vapour pressure of water at saturation vapour pressure of water is 23 mm Hg at that temperature? Options:
  A) 737 mm Hg
  B) 763 mm Hg
  C) 777 mm Hg
  D) 783 mm Hg
  Show Answer
  The correct answer is A .
• Question 63: In which of the following reactions has the oxidation number of nitrogen increased? Options:
  A) 2NO_(g) + Br_2(l) → 2NOBr_(l)
  B) 2NO_(g) + O_2(g) → 2NO_2(g)
  C) FeSO_4(aq) + NO_(g) → Fe(NO)SO_4(s)
  D) 2NO(g) + Cl_2(g) → 2NOCl(l)
  Show Answer
  The correct answer is B .
• Question 64:

  CO_(g) + H₂ O_(g) → CO_2(g) + H_2(g)

  Calculate the standard heat change of the reaction above, if the standard enthalpies of formation of CO_2(g), H₂O_(g) and CO_(g) and CO_(g) in KJ mol ^-1 are - 394 -242 and - 110 respectively.

  Options:
  A) + 262 KJ mol ^-1
  B) - 262 KJ mol ^-1
  C) + 42 KJ mol ^-1
  D) - 42 KJ mol ^-1
  Show Answer
  The correct answer is D .
• Question 65:

  What is the name of the process by which ammonia is produced on an industrial scale?

  Options:
  A) Nitrogenation
  B) Ammoniation
  C) Nitrification
  D) Haber process
  Show Answer
  The correct answer is D .
• Question 66:

  What is the common name for ethanoic acid?

  Options:
  A) Acetic acid
  B) Butyric acid
  C) Propionic acid
  D) Formic acid
  Show Answer
  The correct answer is A .
• Question 67:

  What technique is suitable for separating a binary solution of potassium chloride and potassium trioxochlorate (V)?

  Options:
  A) Fractional crystallization
  B) Fractional distillation
  C) Filtration
  D) Evaporation
  Show Answer
  The correct answer is A .
• Question 68: Bronze is preferred to copper in the making of medals because it Options:
  A) is stronger
  B) can withstand low temperature
  C) is lighter
  D) has low tensile strength
  Show Answer
  The correct answer is A .
• Question 69:

  The two ions responsible for hardness in water are

  Options:
  A) Ca${}^{2+}$ and / or Mg${}^{2+}$
  B) K${}^{+}$ and / or Mg${}^{2+}$
  C) Ca${}^{2+}$ and / or Li${}^{+}$
  D) Ca${}^{2+}$ and / or Na${}^{+}$
  Show Answer
  The correct answer is A .
• Question 70: 0.1 Faraday of electricity was passed through a solution of copper (ll) sulphate. The maximum weight of copper deposited on the cathode would be [Cu = 64] Options:
  A) 64.0g
  B) 32.0g
  C) 16.0g
  D) 6.4 g
  E) 3.2g
  Show Answer
  The correct answer is E .