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 1071: An eruption pollution an environment with gas suspected to be H₂S, a poisonous gas. A residue team should spray the environment with? Options:
  A) water
  B) moist SO₂
  C) acidified KMnO₄ and water
  D) water, acidified KMnO₄ and oxygen
  Show Answer
  The correct answer is B .
• Question 1072:

  What is the trend for ionization energy across a period in the periodic table?

  Options:
  A) Increases from left to right.
  B) Remains constant
  C) Varies randomly
  D) Decreases from left to right
  Show Answer
  The correct answer is A .
• Question 1073: What will happen if an aluminium spoon is used to stir a solution of iron (II) trioxonitrates (V)? Options:
  A) The spoon will be oxidized while the iron (II) ions will be reduced to the metal
  B) The spoon will increase in size
  C) The spoon will be reduced while the iron (II) ions will be oxidized
  D) The spoon will be reduced
  Show Answer
  The correct answer is A .
• Question 1074: When 50cm² of a saturated solution of sugar of molar mass 342 g at 40^oC was evaporated to dryness, 34.2g of dry solid was obtained. The solubility of sugar at 40^oC is Options:
  A) 2.0 mol dm^-3
  B) 3.5 mol dm^-3
  C) 7.0 mol dm^-3
  D) 10.0 mol dm^-3
  Show Answer
  The correct answer is A .
• Question 1075: In the oil drop experiment, Millikan determined the? Options:
  A) charge to mass ratio of the electron
  B) mass of the electron
  C) charge of the electron
  D) mass of the proton
  Show Answer
  The correct answer is C .
• Question 1076: A piece of filter paper moistened with lead (ll) ethanoate solution turns black when the paper is dropped into a gas likely to be Options:
  A) sulphur (VI) oxide
  B) hydrogen chloride
  C) sulphur (VI) oxide
  D) hydrogen sulphide
  Show Answer
  The correct answer is D .
• Question 1077:

  

  The compound above exhibits

  Options:
  A) geometric isomerism
  B) optical isomerism
  C) structural isomerism
  D) positional isomerism
  Show Answer
  The correct answer is B .
• Question 1078:

  What is the empirical formula of a compound containing 40.00% carbon, 6.67% hydrogen, and 53.33% oxygen by mass?

  Options:
  A) C${}_4$H${}_8$O${}_4$
  B) CH${}_2$O
  C) C${}_2$H${}_4$O${}_2$
  D) C${}_3$H${}_6$O${}_3$
  Show Answer
  The correct answer is B .
• Question 1079: The oxidation number of manganese in KMnO₄ is? Options:
  A) +1
  B) +3
  C) +5
  D) +7
  E) +2
  Show Answer
  The correct answer is D .
• Question 1080: Which of the following silver halides is readily soluble in ammonium hydroxide? Options:
  A) Agl
  B) AgBr
  C) AgCl
  D) AgF
  E) None of the above
  Show Answer
  The correct answer is C .