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 1971: The knowledge of half-life can be used to Options:
  A) create an element
  B) detect an element
  C) spilt an element
  D) irradiate an element
  Show Answer
  The correct answer is B .
• Question 1972:

  The reactions involving simultaneous oxidation and reduction?

  Options:
  A) Automatic reactions
  B) Alternate reactions
  C) Reduction agency
  D) Redox reactions
  Show Answer
  The correct answer is D .
• Question 1973:

  If gas A has a molar mass of 32 g/mol and gas B has a molar mass of 64 g/mol, what is the ratio of their diffusion rates?

  Options:
  A) 2:1
  B) 1:2
  C) 1:1
  D) 1:4
  Show Answer
  The correct answer is A .
• Question 1974:

  X + Y → Z. The rate equation for the chemical reaction above is ((-Δ[x])/Δt) = K[X]²[Y].

  The overall order of the reaction is

  Options:
  A) 0.0
  B) 1.0
  C) 2.0
  D) 3.09
  Show Answer
  The correct answer is D .
• Question 1975: Which of the following are the products of the reaction between CH₃COOH and CI₂ in sunlight? Options:
  A) CICH₂COOH + HCI
  B) CH₃COCI + HOCI
  C) CH₃COOCI + HCI
  D) CH₃COCI + HO₂
  Show Answer
  The correct answer is A .
• Question 1976:

  Which of the following factors will speed up the rate of evolution of carbon (iv) oxide in the reaction below?

  2HCl + CaCO${}_3$ → CaCl${}_2$ + H${}_2$O + CO${}_2$

  Options:
  A) Increasing the concentration of the acid
  B) Increasing the surface area of CaCO${}_3$
  C) A and B
  D) Reducing the concentration of the acid
  Show Answer
  The correct answer is C .
• Question 1977: Chlorine gas is prepared in the laboratory by Options:
  A) adding concentrated hydrochloric acid to solid manganese (IV) oxide
  B) aciding concentrated tetraoxosulphate (VI) acid to solid sodium chloride
  C) dropping concentrated hydrochloric acid onto potassium tetraoxomanganate (VI) crystals
  D) aciding concentrated tetraoxosulphate (VI) acid to hydrochloric acid
  Show Answer
  The correct answer is A .
• Question 1978: Which of the following processes leads to increase in entropy? Options:
  A) Mixing a sample of NaCl and sand
  B) Condensation of water vapour
  C) Boiling a sample of water
  D) Cooling a saturated solution
  Show Answer
  The correct answer is C .
• Question 1979:

  A blue litmus paper turns red when dipped into a solution. What does this indicate about the solution?

  Options:
  A) The solution is basic
  B) The solution is neutral
  C) The solution is acidic
  D) The litmus paper is faulty
  Show Answer
  The correct answer is C .
• Question 1980: Which of the following methods may be used to prepare trioxonitrate (V) acid (nitric acid) in the laboratory? Options:
  A) Heating ammonia gas with tetraoxosulphate (VI) acid
  B) Heating ammonium trioxonitrate (V) with tetraoxosulphate (VI) acid
  C) Heating sodium trioxonitrate (V) with tetraoxosulphate (VI) acid
  D) Heating potassium trioxonitrate (V) with calcium hydroxide
  E) Heating a mixture of ammonia gas and oxygen.
  Show Answer
  The correct answer is C .