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 571:

  The periodic classification is an arrangement of the elements

  Options:
  A) atomic weights
  B) isotopic weights
  C) molecular weights
  D) atomic numbers
  Show Answer
  The correct answer is D .
• Question 572:

  SO${}_3$ is not directly dissolved in water in the industrial preparation of H${}_2$SO${}_4$ by the contact process because

  Options:
  A) SO${}_3$ is an acidic gas
  B) Acid is usually added to water and not water to acid
  C) The reaction between SO${}_3$ and water is violently exothermic
  D) SO${}_3$ does not dissolve readily in water
  Show Answer
  The correct answer is C .
• Question 573: Solutions X, Y, and Z have PH values 3.0. 5. 0 and 9. 0 respectively. Which of the following statements is correct? Options:
  A) All the solutions are acidic
  B) All the solutions are basic
  C) Y and Z are more acidic than water
  D) Y is more acidic than X
  E) Z is the least acidic
  Show Answer
  The correct answer is E .
• Question 574: 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 575:

  In the extraction of iron, hot air is introduced into the blast furnacethrough?

  Options:
  A) valves
  B) open-hearths
  C) arcs
  D) tuyeres
  Show Answer
  The correct answer is D .
• Question 576: How many cations will be produced from a solution of potassium aluminium tetraoxosulphate (VI)? Options:
  A) 3
  B) 4
  C) 1
  D) 2
  Show Answer
  The correct answer is D .
• Question 577: Environmental pollution is worsened by the release from the automobile exhaust of Options:
  A) water vapour
  B) steam
  C) smoke
  D) heavy metals
  E) steam and smoke
  Show Answer
  The correct answer is D .
• Question 578:

  How many electrons will be found in the nucleus of an atom with mass number 23 and 17 neutrons?

  Options:
  A) none
  B) 6
  C) 7
  D) 8
  Show Answer
  The correct answer is A .
• Question 579: The gas that can be dried using concentrated tetraoxosulphate (VI) acid is Options:
  A) hydrogen bromide
  B) Sulphur (IV) oxide
  C) hydrogen sulphide
  D) ammonia
  Show Answer
  The correct answer is B .
• Question 580: The boiling point of water, ethanol, toluene and butan-2-ol are 373.0k, 351.3k, 383.6k and 372.5k respectively. Which liquid has the highest vapour pressure at 323.0k? Options:
  A) water
  B) toluene
  C) ethanol
  D) butan-2-ol
  E) none
  Show Answer
  The correct answer is C .