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 1371: Which of the following reaction is endothermic? Options:
  A) C_(s) + O_2(g) → CO_2(g)
  B) CaO_(s) + H₂O_(l) → Ca(OH)_2(s)
  C) C_(s) + H₂O_(g) → CO_(g) + H_2(g)
  D) HCl_(aq) + NaOH_(aq) → NaCl_(aq) + H₂O_(l)
  Show Answer
  The correct answer is C .
• Question 1372: In which of the following is the oxidation number of sulphur equal to -2? Options:
  A) SO₃
  B) S₈
  C) H₂S
  D) SO₂
  Show Answer
  The correct answer is C .
• Question 1373: An organic compound containing 40.1% carbon and 6.6% hydrogen has an empirical formula of? Options:
  A) C₂H₄O₂
  B) C₂H₃O₂
  C) CH₂O
  D) CH₃O
  Show Answer
  The correct answer is C .
• Question 1374:

  Deliquescent substances are also?

  Options:
  A) efflorescent
  B) anhydrous
  C) hygroscopic
  D) insoluble
  Show Answer
  The correct answer is C .
• Question 1375: The knowledge of half-life can be used to Options:
  A) create an element
  B) detect an element
  C) spilt an element
  D) irradiate an element
  Show Answer
  The correct answer is B .
• Question 1376: How many structural isomers can be written for the alkyl bromide, C₄H₉Br? Options:
  A) 3
  B) 4
  C) 6
  D) 8
  Show Answer
  The correct answer is B .
• Question 1377: The ratio of the initial to final pressure of a given mass of gas is 1:1.5. Calculate the final volume of the gas if the initial volume was 300 cm³ at the same temperature Options:
  A) 120 cm³
  B) 200 cm³
  C) 450 cm³
  D) 750 cm³
  Show Answer
  The correct answer is B .
• Question 1378:

  Balance the following redox reaction:
  Fe${}_2$O${}_3$+ CO Fe + CO${}_2$

  Options:
  A) Fe${}_2$O${}_3$ + CO → 2Fe + 2CO${}_2$
  B) 2Fe${}_2$O${}_3$ + 3CO → 4Fe + 3CO${}_2$
  C) Fe${}_2$O${}_3$ + 2CO → 2Fe + 2CO${}_2$
  D) Fe${}_2$O${}_3$ + 3CO → 2Fe + 3CO${}_2$
  Show Answer
  The correct answer is D .
• Question 1379:

  Crude petroleum is converted to useful products by the processof?

  Options:
  A) fractional crystallization
  B) fractional distillation
  C) filtration
  D) chromatography
  Show Answer
  The correct answer is B .
• Question 1380: The reaction of carbide with water gives Options:
  A) ethyne
  B) ethene
  C) ethane
  D) ethanal
  Show Answer
  The correct answer is A .