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 581: A decrease in atomic size and an increase in nuclear charge across a period lead to Options:
  A) an increase in the tendency to lose electron
  B) an increase in chemical reactivity
  C) a decrease in electropositivity
  D) a decrease in covalency in bond formation
  Show Answer
  The correct answer is B .
• Question 582: Nuclear fission involves the splitting of a heavy element into two nuclei of Options:
  A) nearly equal masses with a relaese of energy and radiaton
  B) equal masses with a relaese of energy
  C) equal masses with a release of energy and radiation
  D) unequal masses without any relaese of energy
  Show Answer
  The correct answer is A .
• Question 583: wH₂SO₄ + xAI(OH)₃ → yH₂O + = zAI₂(SO₄)₃. The respective values of w.x.y and z in the equation above are? Options:
  A) 2,2,5 and 1
  B) 3,2,5 and 2
  C) 3,2,6 and 1
  D) 2,2,6 and 2
  Show Answer
  The correct answer is C .
• Question 584:

  n monosaccharide $\underset{Q}{\stackrel{P}{\rightleftharpoons }}$ polysaccharide -n water.

  In the process above, P and Q respectively represent

  Options:
  A) Condensation and hydrolysis
  B) Fermentation and condensation
  C) Polymerization and hydrolysis
  D) Polymerization and condensation
  Show Answer
  The correct answer is A .
• Question 585: A major process involved in the softening of hard water is the? Options:
  A) conversation of a soluble calcium salt to its trioxoncarbonate (lV)
  B) decomposition of calcium rioxocarbonate (lV)
  C) conversion of an insoluble calcium salts to its trioxocarbonate (lV)
  D) oxidation of calcium atoms to its ions
  Show Answer
  The correct answer is A .
• Question 586:

  The molecular shape and bond angle of water are respectively

  Options:
  A) linear, 180°
  B) bent, 109.5°
  C) tetrahedral, 109.5°
  D) bent, 105°
  Show Answer
  The correct answer is D .
• Question 587: 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 588: Terylene is synthesized from ethane- 1, 2-diol and benzene - 1, 4-dicarboxylic acid by? Options:
  A) addition reaction
  B) condensation reaction
  C) elimination reaction
  D) substitution reaction
  Show Answer
  The correct answer is B .
• Question 589: A mixture of starch solution and potassium iodide was placed in a test tube. On adding dilute tetraoxosulphate (lV) acid and then K₂Cr₂O₇ solutions, a blue-black colour was produced. In this reaction, the? Options:
  A) iodide is oxidized
  B) tetraoxosulphate (Vl) acid acts as an oxidizing agent
  C) starch has been oxidized
  D) K₂Cr₂O₇ is oxidized
  Show Answer
  The correct answer is C .
• Question 590:

  Which of the following gases will rekindle a brightly splint?

  Options:
  A) NO${}_2$
  B) NO
  C) N${}_2$O
  D) CL${}_2$
  Show Answer
  The correct answer is C .