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 1261:

  What is the sum of the oxidation numbers in a neutral compound?

  Options:
  A) +2
  B) -1
  C) 0
  D) +1
  Show Answer
  The correct answer is C .
• Question 1262: Which of the following samples will react fastest with dilute trioxonitrate (V) acid? Options:
  A) 5 g of lumps of CacO₃ at 25°C
  B) 5 g of powered CacO₃ at 25°
  C) 5 g of lumps of CaCO₃ at 50°C
  D) 5 g of powered CaCO₃ AT 50°C
  Show Answer
  The correct answer is D .
• Question 1263: 60cm³ of hydrogen are sparked with 20cm³ of oxygen at 100°C and 1 atmosphere. The total volume of the residual gases is? Options:
  A) 60 cm³
  B) 10 cm³
  C) 40 cm³
  D) 30 cm³
  E) 70 cm³
  Show Answer
  The correct answer is A .
• Question 1264: Tin is unaffected by air at ordinary temperature due to its Options:
  A) Low melting point
  B) Weak electropositive character
  C) High boiling point
  D) White lustrous appearance
  Show Answer
  The correct answer is A .
• Question 1265: Which of the following properties is not peculiar to matter? Options:
  A) Kinetic energy of particles increases from solid to gas
  B) Random motion of particles increases from gas to solid
  C) Orderliness of particles increases from gas to liquid
  D) Random motion of particles increases from liquid to gas
  Show Answer
  The correct answer is B .
• Question 1266:

  

  In the diagram above, the mixture of the solids P and Q can be separated by

  Options:
  A) distillation
  B) fractional distillation
  C) crystallization
  D) fractional crystallization
  Show Answer
  The correct answer is C .
• Question 1267:

  Zn + 2HCL ZnCl${}_2$ + H${}_2$

  What happens to zinc in the above reaction?

  Options:
  A) oxidized
  B) a reactant
  C) reduced
  D) a metal
  Show Answer
  The correct answer is A .
• Question 1268:

  A gaseous metallic chloride MCl consists of 20.22% of M by mass. The formula of the chloride is?

  [ M = 27, Cl = 35.5]

  Options:
  A) MCl
  B) MCl${}_2$
  C) MCl${}_3$
  D) M${}_2$Cl${}_6$
  Show Answer
  The correct answer is C .
• Question 1269: In the reaction NH₃ + H⁺ → NH₄⁺, the bond formed results from? Options:
  A) an electron transferred from NH₃ + H⁺
  B) an electron pair donated by NH₃
  C) an electron pair equally shared
  D) an electron pair donated by H⁺
  E) an electron tarnsferred from H⁺ to NH₃
  Show Answer
  The correct answer is B .
• Question 1270: Kerosine is commonly used to remove the red colour stain of palm oil from cloths because it Options:
  A) helps to spread the oil over a larger surface area
  B) react with the oil to form an odourless compound
  C) makes the oil evaporate easily by dissolving it
  D) helps to dilute the oil and reduce its colour
  Show Answer
  The correct answer is C .