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 601: Given that the molecular mass of iron is 56 and that of oxygen is 16, how many moles of iron(iii)oxide will be contained in 1kg of the compound? Options:
  A) 25.0 moles
  B) 12.5 moless
  C) 6.25 moles
  D) 3.125 moles
  E) 0.625 moles
  Show Answer
  The correct answer is C .
• Question 602:

  An organic functional group which can likely decolorize ammoniacal silver nitrate is?

  Options:
  A) alkene
  B) alkane
  C) alkyne
  D) alkanol
  Show Answer
  The correct answer is C .
• Question 603:

  Four elements P, Q, R and S have atomic numbers of 4, 10, 12 and 14 respectively. Which of these elements is noble gas? 

  Options:
  A) P
  B) Q
  C) R
  D) S
  Show Answer
  The correct answer is B .
• Question 604:

  Chlorine, consisting of two isotopes of mass numbers 35 and 37, has an atomic mass of 35.5.

  The relative abundance of the isotope of mass number 37 is?

  Options:
  A) 20
  B) 25
  C) 50
  D) 75
  Show Answer
  The correct answer is B .
• Question 605: The pollutant that contributes to the depletion of the ozone layer is Options:
  A) CFCs
  B) NO₂
  C) SO₂
  D) CO
  Show Answer
  The correct answer is A .
• Question 606: Which of the following fraction is used as raw material for the cracking process? Options:
  A) kerosine
  B) lubricating oil
  C) bitumen
  D) diesel oils
  Show Answer
  The correct answer is D .
• Question 607: A pair of compounds that can be used to generate a gas which has physiological effect on human beings is Options:
  A) sodium trioxonitrate (V) and calcium chloride
  B) sodium dioxonitrate (III) and ammonium chloride
  C) sodium trioxonitrate (V) and ammonium chloride
  D) sodium dioxonitrate (III) and potassium chloride
  Show Answer
  The correct answer is A .
• Question 608:

  Which of the following reactions would be expected to have the highest entropy change?

  Options:
  A) Liquid → Gas
  B) Solid → Liquid
  C) Gas → Liquid
  D) Gas → Solid
  Show Answer
  The correct answer is A .
• Question 609: Which of the following gases contains the least number of atoms at s.t.p? Options:
  A) 1 mole of butane
  B) 3 mole of ozone
  C) 4 mole of chlorine
  D) 7 mole of argon
  Show Answer
  The correct answer is A .
• Question 610:

  Which of the following factors does NOT affect the rate of a chemical reaction?

  Options:
  A) Concentration of reactants
  B) Presence of a catalyst
  C) Molecular weight of products
  D) Temperature
  Show Answer
  The correct answer is C .