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 11: A few drops of concentrated PCI are added to about 10cm³ of a solution of pH 3.4. The pH of the resulting mixtures is? Options:
  A) less than 3.4
  B) greater than 3.4
  C) unaltered
  D) the same as that of pure water
  Show Answer
  The correct answer is C .
• Question 12: A particle that contains a protons, 10 neutrons and 10 electrons is Options:
  A) positive ion
  B) neutral atom of a metal
  C) neutral atom of a non-metal
  D) negative ion
  Show Answer
  The correct answer is D .
• Question 13: C₃H_8(g) + 50_2(g) → 4H₂O + 3CO_2(g). Form the equation above the volume of oxygen at s.t.p. required to burn 50cm³ of propane is? Options:
  A) 250 cm³
  B) 150 cm³
  C) 100 cm ³
  D) 50 cm³
  Show Answer
  The correct answer is A .
• Question 14:

  

  The elections or two atoms Y and Z are arranged in shes as shown above. The bond formed between the atoms of Y and Z is

  Options:
  A) ionic
  B) convalent
  C) dative
  D) metallic
  Show Answer
  The correct answer is B .
• Question 15: The fundamental difference between the three states of matter is the Options:
  A) shape of their particles
  B) number of particles in each state
  C) shape of the container they occupy
  D) degree of movement of their particles
  Show Answer
  The correct answer is D .
• Question 16: 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 .
• Question 17: What is the valence shell electron configuration of the element with atomic number 17? Options:
  A) 1s² 2s² 2p⁶ 3s² 3p⁴
  B) 1s² 2s² 2p⁶ 3s² 3p⁵
  C) 2s² 2p⁶
  D) 3s² 3p⁵
  Show Answer
  The correct answer is B .
• Question 18:

  In the reaction H_2(g)O $\to$ H_2(g) + 1/2O_2(g)

  ΔH = -2436000 KJ, which of the following has no effect on the equilibrium position?

  Options:
  A) Adding argon to the system
  B) Lowering the temperature
  C) Adding hydrogen to the system
  D) Decreasing the pressure
  E) Increasing the temperature
  Show Answer
  The correct answer is A .
• Question 19: Water can be obtained as the only product during Options:
  A) combustion of hydrocarbons
  B) neutralization of an acid by base
  C) combustion of hydrogen
  D) electrolysis of brine
  E) boiling water
  Show Answer
  The correct answer is C .
• Question 20:

  Which of the following can be obtained by fractional distillation? 

  Options:
  A) Nitrogen from liquid air
  B) Sodium Chloride from sea water
  C) Iodine from solution of Iodine in carbon tetrachloride
  D) Sulphur from the solution of sulphur in carbon disulphide
  Show Answer
  The correct answer is A .