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 81: Hardening of an oil may achieved by? Options:
  A) boiling the oil with water
  B) boiling the oil with a catalyst
  C) treating the oil with sodium hydroxide
  D) treating the oil with hydrogen and catalyst
  E) distilling oil under reduced pressure
  Show Answer
  The correct answer is D .
• Question 82: The reaction of carbide with water gives Options:
  A) ethyne
  B) ethene
  C) ethane
  D) ethanal
  Show Answer
  The correct answer is A .
• Question 83:

  

  Use the graph above to answer this question.

  A sample, X, solid at room temperature, was melted, heated to a temperature of 358 K and allowed to cool as shown in OPQR. The section OP suggests that X is in the

  Options:
  A) liquid sate
  B) solid/liquid state
  C) solid state
  D) gaseous state
  Show Answer
  The correct answer is A .
• Question 84: 2SO_2(g) + O_2(g) 2SO₃. In the reaction above, the standard heats of formation of SO_2(g) and SO_3(g) are -297 KJ mol^-1 respectively. The heat change of the reaction is? Options:
  A) -99 kJ mol^-
  B) -198 kJ mol^-
  C) +198 kJ mol^-
  D) +683kJ mol^-
  Show Answer
  The correct answer is B .
• Question 85: Which of the following will produce a solution with pH less than 7 at equivalent point? Options:
  A) HNO ₃ +NaOH
  B) H ₂SO ₄ + KOH
  C) HC +Mg (OH) ₂
  D) HNO ₃ + KOH
  Show Answer
  The correct answer is C .
• Question 86: Millikan's contributions to the development of atomic theory is the determination of Options:
  A) charge on electron
  B) positive rays
  C) charge to mass ratio
  D) cathode rays
  Show Answer
  The correct answer is A .
• Question 87: Hydrogen sulphide gas can act as Options:
  A) an oxidizing agent
  B) a dehydrating agent
  C) a bleaching agent
  D) a precipitating agent
  Show Answer
  The correct answer is D .
• Question 88: The distance between the nuclei of chlorine atoms in a chlorine molecule is 0.194 mm. The atomic radius of chlorine atom is Options:
  A) 0.097 mm
  B) 0.194 mm
  C) 0.388 mm
  D) 2.388 mm
  Show Answer
  The correct answer is A .
• Question 89: The Arrhenius equation expresses the relationship between the speed of a reaction and its Options:
  A) Molecular collision
  B) Heat of reaction
  C) Catalyst
  D) Activation energy
  Show Answer
  The correct answer is A .
• Question 90: The bond which joins two ethanoic acid molecules in the liquid state is Options:
  A) a covalent bond
  B) an ionic bond
  C) a dative covalent bond
  D) a hydrogen bond
  Show Answer
  The correct answer is D .