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 1801: Naphthalene when heated melts at 354 K (81 ^oC). At this temperature the molecules of naphthalene Options:
  A) decompose into smaller molecules
  B) change their shape
  C) are oxidized by atmospheric oxygen
  D) contract
  E) become mobile as the inter molecular forces are broken
  Show Answer
  The correct answer is E .
• Question 1802: In the Haber process for the manufacture of ammonia, finely divided iron is used as Options:
  A) an ionizing agent
  B) a reducing agent
  C) a catalyst
  D) a dehydrating agent
  E) an oxidizing agent
  Show Answer
  The correct answer is C .
• Question 1803:

  I. H = 1s¹ II. N = 1s² 2s² p³ III. O = 1s² 2s² p⁴ IV. Zn = 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰

  From the above, which of the following pairs is like to be paramagnetic?

  Options:
  A) I and II
  B) I and III
  C) I and IV
  D) III and IV
  Show Answer
  The correct answer is A .
• Question 1804:

  

  The IUPAC nomenclature of the organic compound with the above structural formula is

  Options:
  A) 3-ethyl-2,5-dimethylhexane
  B) 4-ethyl-2,5-dimethylhexane
  C) 3-ethyl-2,5,5 - trimethylpentane
  D) 3-ethyl, 1,1,4-trimethylpentane
  Show Answer
  The correct answer is A .
• Question 1805: The salt formed from a reaction between citric acid and sodium hydroxide in solution will be Options:
  A) acidic
  B) basic
  C) complex
  D) neutral
  Show Answer
  The correct answer is B .
• Question 1806:

  

  The solubility curve of a solid X (molecular mass = 160) is as show above 1,000 cm³ of a saturated solution of X at 80^oC. The weight of X crystalized out would be

  Options:
  A) 10 g
  B) 12 g
  C) 14 g
  D) 16 g
  E) 18 g
  Show Answer
  The correct answer is D .
• Question 1807:

  Which important nitrogen-containing compound is produced in Haber's process?

  Options:
  A) NH${}_3$
  B) NO${}_2$
  C) NO
  D) HNO${}_3$
  Show Answer
  The correct answer is A .
• Question 1808: The scale of a chemical balance is made of iron plate and coated with copper electrolytically because Options:
  A) iron is less susceptible to corrosion than copper
  B) copper is twice as less susceptitible to corrosion as iron
  C) copper is less susceptible to corrosion than iron
  D) copper and iron are equally susceptible to corrosion
  Show Answer
  The correct answer is C .
• Question 1809: The carbon atoms on ethane are? Options:
  A) sp² hybridized
  B) sp³ hybridized
  C) sp²d hybridized
  D) sp hybridized
  Show Answer
  The correct answer is B .
• Question 1810:

  200 cm³ of air was passed over heated copper in a syringe several times to produce copper (II) oxide.

  When cooled, the final volume of air recorded was 158cm³. Estimate the percentage of oxygen in the air?

  Options:
  A) 31%
  B) 27%
  C) 21%
  D) 19%
  Show Answer
  The correct answer is C .