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:
  

  Use the section of the periodic table above to answer this question.

  Which letter represents a non-metal that is a solid at room temperature?

  Options:
  A) T
  B) R
  C) J
  D) X
  Show Answer
  The correct answer is A .
• Question 42: In the production of soap, concentrated sodium chloride solution is added to Options:
  A) increase the solubility of soap
  B) decrease the solubility of the soap
  C) saponify the soap
  D) emulsify the soap
  Show Answer
  The correct answer is B .
• Question 43: A gas occupies 30.0 dm³ at S.T.P. What volume would it occupy at 91^oC and 380 mm Hg? Options:
  A) 20. 0dm³
  B) 40.0dm³
  C) 60. 0dm³
  D) 80. 0dm³
  E) 100. 0dm³
  Show Answer
  The correct answer is D .
• Question 44: Electronic configuration of an elements 13x in the subsidiary energy level is Options:
  A) $1s^{2}2s^{2}2p^{6}3s^{2}3p^1$
  B) $1s^{2}2s^{2}2p^{4}3p^{1}3s^1$
  C) $1s^{2}2s^{2}2p^{6}3s^{2}3p^3$
  D) $1s^{1}2s^{2}2p^{6}3s^{2}3p^4$
  Show Answer
  The correct answer is A .
• Question 45:

  What is the percentage by mass of oxygen in Al₂(SO₄)₃. 2H₂O?

  [Al = 27, S = 32, H = 1, O = 16]

  Options:
  A) 14.29%
  B) 25.39%
  C) 50.79%
  D) 59.25%
  Show Answer
  The correct answer is D .
• Question 46:

  The fourteen elements (atomic number 90-103) after actinium are called?

  Options:
  A) Actinoids
  B) Nucleotides
  C) Pre-actinum elements
  D) Atomic elements
  Show Answer
  The correct answer is A .
• Question 47:

  Which of the following is a primary constituent of crude oil?

  Options:
  A) Pentane
  B) Ethanol
  C) Heptane
  D) Methane
  Show Answer
  The correct answer is D .
• Question 48: Coal fire should not be used in poorly ventilated rooms because ? Options:
  A) of the accumulation of CO₂ which causes dep sleep
  B) it is usually too hot
  C) of the acumulation of CO which causes suffocation
  D) it removes most most of the gases in the rooms
  Show Answer
  The correct answer is C .
• Question 49:

  

  The above orbital diagram shown the electronic configuration of

  Options:
  A) chlorine
  B) nitrogen
  C) calcium
  D) neon
  Show Answer
  The correct answer is B .
• Question 50: The gas that can best be collected by downward displacement of air is Options:
  A) Chlorine
  B) Sulphur (IV) oxide
  C) Ammonia
  D) Carbon (IV) oxide
  Show Answer
  The correct answer is C .