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 541:

  What is the concentration of a solution containing 2g of NaOH in 100cm³ of solution?
  [Na = 23, O = 16, H = 1]

  Options:
  A) 0.40 mol dm^-3
  B) 0.50 mol dm^-3
  C) 0.05 mol dm^-3
  D) 0.30 mol dm^-3
  Show Answer
  The correct answer is B .
• Question 542: A substance S is isomorphous with another substance R. When a tiny crystals of S is added into a supersaturated solution of R? Options:
  A) S dissolves in the solution
  B) crystals of R are precipitated
  C) there is no observable change
  D) R and S react to generate heat
  Show Answer
  The correct answer is B .
• Question 543: 4.0 g of sodium hydroxide in 250 cm³ of solution contains? Options:
  A) 0.40 moles per dm³
  B) 0.10 moles per dm³
  C) 0.04 moles per dm³
  D) 0.02 moles per dm³
  Show Answer
  The correct answer is A .
• Question 544: 2 - methyl propan -2- ol is an example of a Options:
  A) primary alkanol
  B) secondary alkanol
  C) tertiary alkanol
  D) quartenary alkanol
  Show Answer
  The correct answer is C .
• Question 545: The major and most effective way of controlling pollution is to Options:
  A) improve machinery so that the substances released from combustion are less harmful
  B) pass strict laws against it by individuals and companies
  C) educate people on the causes and effects of pollution
  D) convert chemical wastes to harmless substances before releasing them into the environment
  Show Answer
  The correct answer is C .
• Question 546:

  Elements in the periodic table are arranged in the order of their

  Options:
  A) atomic numbers
  B) metallic character
  C) mass number
  D) relative atomic mass
  Show Answer
  The correct answer is A .
• Question 547:

  

  The diagram above (Fig.3) shows the energy profile for the reaction A + B + = C + D From this diagram, it is clear that the reaction is

  Options:
  A) spontaneous
  B) isothermal
  C) adiabatic
  D) exothermic
  E) endothermic
  Show Answer
  The correct answer is D .
• Question 548: A solid that absorbs water from he atmosphere and forms an aqueous solution is? Options:
  A) hydrophilic
  B) efforescent
  C) deliquescent
  D) hygroscopic
  Show Answer
  The correct answer is C .
• Question 549: During the electrolysis of a salt of a metal M, a current of 0.5 A flows from for 32 minutes 10 seconds and deposits 0.325 g of M, What is the charge of the metal ion?(M = 65, If = 96,500 C per mole of electron) Options:
  A) 1
  B) 2
  C) 3
  D) 4
  Show Answer
  The correct answer is B .
• Question 550: Three liquids X, Y and Z containing only hydrogen and carbon were burnt on a spoon. X and Y burnt with sooty flames while Z did not. Y is able to discharge the colour of bromine water whereas X and Z cannot. Which of the liquids would be aromatic in nature? Options:
  A) X and Z
  B) Y
  C) X
  D) Z
  Show Answer
  The correct answer is B .