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 381: Coal fire should not be used in poorly ventilated rooms because ? Options:
  A) of the accumulation of CO₂ which causes dep sleep
  B) it is usually too hot
  C) of the acumulation of CO which causes suffocation
  D) it removes most most of the gases in the rooms
  Show Answer
  The correct answer is C .
• Question 382: When sodium dioxonitrate (lll) (NaNO₂) dissolves in water, ∆H is positive. The process of dissolution is Options:
  A) exothermic
  B) endothermic
  C) isothermal
  D) isomeric
  E) hygroscopic
  Show Answer
  The correct answer is B .
• Question 383: A metal is extracted from its ore by the electrolysis of its molten chloride and it displaces lead from lead (ll) trioxonitrate (V) solution. The metal is Options:
  A) copper
  B) aluminium
  C) zinc
  D) sodium
  Show Answer
  The correct answer is D .
• Question 384: Aluminium hydroxide is used in the dyeing industry as a Options:
  A) dye
  B) dispersant
  C) salt
  D) mordant
  Show Answer
  The correct answer is D .
• Question 385: Oxidation of concentrated hydrochloric acid with manganese (IV) oxide liberates a gas used in the? Options:
  A) manufacture of tooth pastes
  B) treatment of simple golitre
  C) vulcanization of rubber
  D) sterilization of water
  Show Answer
  The correct answer is D .
• Question 386: Water can be identified by the use of? Options:
  A) anhydrous copper (II) tetraoxosulphate (VI)
  B) anhydrous sodium trioxocarbonate (IV)
  C) potassium heptaoxochromate (VII)
  D) copper (II) trioxocaronate (IV)
  Show Answer
  The correct answer is A .
• Question 387:

  A correct electrochemical series can be obtained from Na, Ca, Al, Mg, Zn, Fe, Pb, H, Cu, Hg, Ag, Au by interchanging

  Options:
  A) Al and Mg
  B) Zn and Fe
  C) Zn and Pb
  D) Pb and H
  Show Answer
  The correct answer is A .
• Question 388:

  Which of the following is an example of an endothermic reaction?

  Options:
  A) Combustion of propane (C${}_3$H${}_8$) to produce carbon dioxide (CO${}_2$) and water (H${}_2$O).
  B) Burning of methane (CH${}_4$) in the presence of oxygen
  C) Formation of table salt (NaCl) from sodium (Na) and chlorine (Cl${}_2$).
  D) Decomposition of hydrogen peroxide (H${}_2$O${}_2$) into water (H${}_2$O) and oxygen (O${}_2$).
  Show Answer
  The correct answer is D .
• Question 389:

  The volume occupied by 1.58g of a gas at S.T.P is 500cm${}^3$. What is the relative molecular mass of the gas?  [ G.M.V at S.T.P = 22.4dm${}^3$ ]

  Options:
  A) 28
  B) 32
  C) 44
  D) 71
  Show Answer
  The correct answer is D .
• Question 390: Which of the following is the correct order of decreasing activity of the metals Fe, Ca, Al and Na? Options:
  A) Fe> Ca> Al> Na
  B) Na> Ca> Al> Fe
  C) Al> Fe> Na> Ca
  D) Ca> Na> Fe>, Al
  Show Answer
  The correct answer is B .