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 1331:

  In the reaction between sodium hydroxide and tetraoxosulphate (VI) solutions, what volume of 0.5 molar sodium hydroxide would exactly neutralize 10cm${}^3$ of 1.25 molar tetraoxosulphate (vi) acid?

  Options:
  A) 25cm${}^3$
  B) 10cm${}^3$
  C) 20cm${}^3$
  D) 50cm${}^3$
  Show Answer
  The correct answer is D .
• Question 1332: Some metals are extracted from their ores after some preliminary treatments by electrolysis (L), some of both processes (TL). Which set-up in the following for the extraction of ion, copper and aluminium is correct? Options:
  A) lron (L), copper (L) aluminium (T)
  B) lron (T) copper (L) aluminium (T)
  C) lron (TL) copper (TL) aluminium (TL)
  D) Iron (L) copper (T) aluminium (T)
  E) lron (T) copper (L), aluminium (TL)
  Show Answer
  The correct answer is E .
• Question 1333:

  When heat is absorbed during a chemical reaction, the reaction is said to be

  Options:
  A) thermodynamic
  B) exothermic
  C) isothermal
  D) endothermic
  Show Answer
  The correct answer is D .
• Question 1334:

  How many valence electrons are contained in the element ${}_{15}^{31}P$?

  Options:
  A) 3
  B) 4
  C) 15
  D) 31
  Show Answer
  The correct answer is A .
• Question 1335: 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 .
• Question 1336: Which of the following reactions takes place in the cathode compartment during the electrolysis of copper (II) chloride solution? Options:
  A) Cu²⁺ + 2e^- → Cu(s)
  B) 2Cl^- -2e → Cl₂
  C) Cu_(s) -2e → Cu²⁺_(aq)
  D) Cu²⁺_(aq) + 2Cl^-_(aq) → CuCl_2(aq)
  Show Answer
  The correct answer is A .
• Question 1337: The chemical used for coagulation in water purification is Options:
  A) Aluminium tetraoxosulphate (VI)
  B) Copper tetraoxosulphate (VI)
  C) Sodium tetraoxosulphate (VI)
  D) Calcium tetraoxosulphate (VI)
  Show Answer
  The correct answer is A .
• Question 1338: Four elements P,Q,R and S have 1,2,3, and 7 electrons in their outermost shells respectively. The element which is unlikely to be a metal is? Options:
  A) P
  B) Q
  C) R
  D) S
  Show Answer
  The correct answer is D .
• Question 1339:

  

  In the diagram above, the purpose of the asbestos to

  Options:
  A) absorb impurities
  B) catalyze the reaction
  C) solidify the gas
  D) dry the gas
  Show Answer
  The correct answer is B .
• Question 1340:

  

  If in the graph above 1 dm³ of a saturated solution of KCL is cooled from 80^oC, the mass of crystals deposited will be  [K = 39, Cl = 35.5]

  Options:
  A) 7.45 g
  B) 14.90 g
  C) 74.50 g
  D) 149.00 g
  Show Answer
  The correct answer is D .