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 231: A suitable solvent for iodine and nephthalene is Options:
  A) carbon (IV) sulphide
  B) ethanol
  C) water
  D) benzene
  Show Answer
  The correct answer is B .
• Question 232: The rate of a reaction usually decrease in the concentration of reactants because Options:
  A) kinetic energy decrease
  B) temperature increase
  C) speed increases
  D) reactants collision decrease
  Show Answer
  The correct answer is D .
• Question 233: Which of the following statements is an exception in the assumptions of the kinetic theory of gases? Options:
  A) Gases are composed of many elastic particles
  B) The particles are of negligible size
  C) The particles are in constant random motion
  D) The particles are of negligible mass
  E) The particles collide with each other
  Show Answer
  The correct answer is D .
• Question 234: The metal that liberates hydrogen from cold water in bubbles only is Options:
  A) Na
  B) K
  C) Ca
  D) Al
  Show Answer
  The correct answer is C .
• Question 235: In the reaction M + N P;∆H = + QKJ. Which of the following would increase the concentration of the product? Options:
  A) Decreaseing the concentration of N
  B) Increasing the concentration of P
  C) Adding a suitable catalyst
  D) Decreasing the temperature
  E) Increasing the temperature
  Show Answer
  The correct answer is E .
• Question 236: A noble gas with a high power of fog penetration used in aerodrome beacons is Options:
  A) krpton
  B) argon
  C) helium
  D) neon
  Show Answer
  The correct answer is D .
• Question 237: A metal that forms soluble trioxosulphate (IV) ion is Options:
  A) barium
  B) potassium
  C) manganese
  D) aluminium
  Show Answer
  The correct answer is B .
• Question 238: If the ONLY pollutants found in the atmosphere over a city are oxides of nitrogen, suspended lead compounds. carbon monoxide and high levels of methane, the probable source(s) of the pollution must be? Options:
  A) automobile exhaust and biological decomposition
  B) combustion of coal and automobile exhaust
  C) biological decomposition only
  D) combustion of coal, automobile exhaust and biological decomposition
  E) combustion of coal and biological decomposition
  Show Answer
  The correct answer is B .
• Question 239:

  

  The diagram above (Fig.3) shows the energy profile for the reaction A + B + = C + D From this diagram, it is clear that the reaction is

  Options:
  A) spontaneous
  B) isothermal
  C) adiabatic
  D) exothermic
  E) endothermic
  Show Answer
  The correct answer is D .
• Question 240: Which experiment led to the measurement of the charge on an electron? Options:
  A) Mass spectrometric experiment
  B) Oil-drop experiment
  C) Scattering α - particles
  D) Discharge-tube experiment
  Show Answer
  The correct answer is B .