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 2101: Due to the high reactivity of sodium, it is usually stored under Options:
  A) water
  B) mercury
  C) paraffin
  D) phenol
  Show Answer
  The correct answer is C .
• Question 2102:

  To what volume must 300cm${}^3$ of 0.60M sodium hydroxide solution be diluted to give a 0.40M solution?

  Options:
  A) 450cm${}^3$
  B) 300cm${}^3$
  C) 200cm${}^3$
  D) 150cm${}^3$
  Show Answer
  The correct answer is A .
• Question 2103: The solubility curve shows the variation of solute concentration with Options:
  A) volume
  B) temperature
  C) vapour density
  D) pressure
  Show Answer
  The correct answer is B .
• Question 2104:

  

  In the diagram above the activation energy is represented by

  Options:
  A) y - x
  B) x
  C) x - z
  D) y
  Show Answer
  The correct answer is A .
• Question 2105:

  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 2106:

  

  The diagram shown above represents the solubility curves of two salts, X and Y, in water, use this diagram to answer the question. If the molar mass of X is 36 g, the number of moles of X dissolved at 343 K is

  Options:
  A) 0.2 moles
  B) 0.7 moles
  C) 1.5 moles
  D) 2.0 moles
  E) 3.0 moles
  Show Answer
  The correct answer is B .
• Question 2107: Which of these salts will produce its metal, oxygen and nitrogen (IV) oxide on heating? Options:
  A) Silver and trioxonitrate (V)
  B) Sodium trioxonitrate (V)
  C) Calcium trioxonitrate (V)
  D) Lithium trioxonitrate (V)
  Show Answer
  The correct answer is A .
• Question 2108:

  Na₂CO₃ + 2HCI → 2NaCI + H₂O + CO₂. Using the above equation, what volume of carbondioxide, measured at s.t.p is liberated when 53g of sodium carbonate is dissolved in hydrochloric acid?

  (1 mole of gas occupies 22.4 dm³ at s.t.p)

  (Na = 23, C = 12, O = 16)

  Options:
  A) 44.8 dm³
  B) 11.2 dm³
  C) 100.1 dm³
  D) 3.0 dm³
  E) 22.4 dm³
  Show Answer
  The correct answer is B .
• Question 2109: In the reaction Fe + Cu²⁺ $\to$ Fe²⁺ + Cu,iron displaces copper ions to from copper. This is due to the fact that Options:
  A) irn is in the metallic from while the copper is in the ionic from
  B) the atomic weight of copper is greater than that of iron
  C) copper is greater than iron
  D) copper metal has more electrons than iron metal
  E) iron is higher in the electrochemical series than copper
  Show Answer
  The correct answer is E .
• Question 2110:

  

  For which salt in the graph above does the solubility increase most rapidly with rise in temperature?

  Options:
  A) CaSO₄
  B) KNO₃
  C) NaCl
  D) KCl
  Show Answer
  The correct answer is B .