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 1751: The soft solder used for welding and plumbing is alloy of Options:
  A) lead and tin
  B) iron and tin
  C) lead and zinc
  D) iron and zinc
  Show Answer
  The correct answer is A .
• Question 1752:

  

  The name of the compound above is

  Options:
  A) acetic acid
  B) propanal
  C) propanol
  D) ethanoic acid
  E) propanoic acid
  Show Answer
  The correct answer is E .
• Question 1753:

  If the heat of combustion of hydrogen is -285.8kJ,

  What is the heat of formation of water?

  Options:
  A) +571.6 kJ
  B) -571.6 kJ
  C) -285.8 kJ
  D) +285.8 kJ
  Show Answer
  The correct answer is C .
• Question 1754: A pure solid usually melts? Options:
  A) over a wide range of temperature
  B) over a narrow range of temperature
  C) at a lower temperature than the impure one
  D) at the same temperature as the impure one
  Show Answer
  The correct answer is B .
• Question 1755:

  The products of the thermal decomposition of ammonium trioxonitrate(v) are?

  Options:
  A) Nitrogen (I) Oxide and Water
  B) Ammonia and Oxide
  C) Nitrogen and Water
  D) Nitrogen (IV) Oxide and Water
  Show Answer
  The correct answer is A .
• Question 1756: In the industrial production of H₂ from natural gas the CO₂ produced along with the H₂ is removed by Options:
  A) washing under pressure
  B) drying over phosphorus (V) oxide
  C) passing the mixture into lime water
  D) using ammonical copper (I) chloride
  Show Answer
  The correct answer is A .
• Question 1757: The chemicals used to soften hard water involves the addition of Options:
  A) insoluble sodium compounds which from soluble solutions of calcium and magesium
  B) solube soudium compounds which from soluble solutions of calcium and magnesium ions
  C) solube sodium compounds which from insoluble precipitates of calcium and magnesium ions
  D) insoluble precipitates of calcium and magnesium ions
  Show Answer
  The correct answer is C .
• Question 1758:

  Which noble gas is radioactive and is produced as a decay product of uranium and thorium?

  Options:
  A) Argon
  B) Krypton
  C) Radon
  D) Neon
  Show Answer
  The correct answer is C .
• Question 1759: An example of oxidation - reduction enzyme is Options:
  A) amylase
  B) protease
  C) lipase
  D) dehydrogenase
  Show Answer
  The correct answer is D .
• Question 1760: On heating, which of the following compounds will decompose to the free metal, nitrogen (IV) oxide and oxygen? Options:
  A) Ca(NO₃)₂
  B) Cu(NO₃)₂
  C) AgNO₃
  D) NaNO₃
  Show Answer
  The correct answer is C .