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 331: 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 332: The polymer used in making car rear lights is Options:
  A) perspex
  B) bakeelite
  C) polystyrene
  D) polyacrylonitrile
  Show Answer
  The correct answer is A .
• Question 333: Two equal bulbs, one containing ammonia and the other one opened mouth-to mouth to each other at temperature the entropy in the mixture of gases is likely to Options:
  A) remain unchanged
  B) increase
  C) decrease
  D) charge
  Show Answer
  The correct answer is A .
• Question 334: The constituent common to duralumin and alnico is Options:
  A) Co
  B) Mn
  C) Al
  D) Mg
  Show Answer
  The correct answer is C .
• Question 335: Four elements W, X, Y and Z have atomic number 2,6,16 and 20 respectively. Which of these elements is a metal? Options:
  A) X
  B) W
  C) Z
  D) Y
  Show Answer
  The correct answer is C .
• Question 336:

  Which halogen is a gas at room temperature and is pale yellow in color?

  Options:
  A) Chlorine (Cl)
  B) Fluorine (F)
  C) Iodine (I)
  D) Bromine (Br)
  Show Answer
  The correct answer is B .
• Question 337:

  The fourteen elements (atomic number 90-103) after actinium are called?

  Options:
  A) Actinoids
  B) Nucleotides
  C) Pre-actinum elements
  D) Atomic elements
  Show Answer
  The correct answer is A .
• Question 338:

  The process by which salt and water reacted in a limited way to form an acid or abase is?

  Options:
  A) Neutral process
  B) Basic acidic process
  C) Hydrolysis
  D) Sublimation
  Show Answer
  The correct answer is C .
• Question 339: The presence of an impurity in substance will cause the melting point to Options:
  A) be zero
  B) reduce
  C) increase
  D) be stable
  Show Answer
  The correct answer is B .
• Question 340: Two organic compounds K and L were treated with a few drops of Fehling's solutions respectively . K formed a brick-red precipitate while L, remains unaffected. The compound K is an Options:
  A) alkanol
  B) alkane
  C) alkanal
  D) alkanone
  Show Answer
  The correct answer is C .