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 561: A major process involved in the softening of hard water is the? Options:
  A) conversation of a soluble calcium salt to its trioxoncarbonate (lV)
  B) decomposition of calcium rioxocarbonate (lV)
  C) conversion of an insoluble calcium salts to its trioxocarbonate (lV)
  D) oxidation of calcium atoms to its ions
  Show Answer
  The correct answer is A .
• Question 562: The constituent of air necessary in the rusting process are Options:
  A) O₂ and H₂O
  B) Ar and CO₂
  C) CO₂ and H₂O
  D) O₂ and CO₂
  Show Answer
  The correct answer is D .
• Question 563:

  Identify the reducing agent in the following reaction:
  Zn + CuSO${}_4$ ZnSO${}_4$ + Cu

  Options:
  A) Cu
  B) Zn
  C) ZnSO${}_4$
  D) CuSO${}_4$
  Show Answer
  The correct answer is B .
• Question 564:

  

  In the graph above, the activation energy of the catalyzed reaction is

  Options:
  A) 100KJ
  B) 300KJ
  C) 250KJ
  D) 200KJ
  Show Answer
  The correct answer is A .
• Question 565: Calculate the relative molecular mass of Limestone CaCO3, (Ca = 40, C =12, O = 16) Options:
  A) 56
  B) 100
  C) 76
  D) 90
  Show Answer
  The correct answer is B .
• Question 566:

  The equilibrium reaction between copper (l) chloride and chlorine at 25^oC and 1 atmosphere is represented by the equation:

  2CuCl +Cl₂ ⇌ 2 CuCl₂ ∆H = - 166 KJ. Which of the following statements is TRUE for the reaction, pressure remaining constant?

  Options:
  A) more CuCl is formed at 40^oC
  B) more CuCl₂ is formed at 10^oC
  C) Less CuCl₂ is formed at 10^oC
  D) there is no change in the amount of CuCl₂ formed at 40^oC and10^oC
  E) more CuCl is consumed at 40^oC
  Show Answer
  The correct answer is B .
• Question 567: What volume of 1.5M solution of KOH would contain 0.045 moles Options:
  A) 67.50 cm³
  B) 30.00 cm³
  C) 6.75 cm³
  D) 3.00 cm³
  Show Answer
  The correct answer is B .
• Question 568: Cu₂S_(s) + O2(g) = 2CU_(s) + SO2_2(g) Options:
  A) +1 to 0
  B) 0 to +2
  C) +2 to +1
  D) 0 to +1
  Show Answer
  The correct answer is A .
• Question 569: During the vulcanization of rubber, sulphur is added to Options:
  A) Break down rubber polymer
  B) Lengthen the chain of rubber
  C) Bind rubber molecules together
  D) Act as a catalyst
  Show Answer
  The correct answer is C .
• Question 570:

  A basic postulate of the kinetic theory of gases is that the molecules of a gas move in straight lines between collisions. This implies that

  Options:
  A) collisions are perfectly elastic
  B) forces of repulsion exist
  C) forces of repulsion and attraction are in equilibrium
  D) collisions are inelastic
  Show Answer
  The correct answer is B .