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 141: Deliquescent substance are used for Options:
  A) Cooling
  B) Wetting
  C) Melting
  D) Drying
  Show Answer
  The correct answer is D .
• Question 142:

  The fourteen elements (atomic number 90-103) after actinium are called?

  Options:
  A) Actinoids
  B) Nucleotides
  C) Pre-actinum elements
  D) Atomic elements
  Show Answer
  The correct answer is A .
• Question 143:

  How many electrons will be found in the nucleus of an atom with mass number 23 and 17 neutrons?

  Options:
  A) none
  B) 6
  C) 7
  D) 8
  Show Answer
  The correct answer is A .
• Question 144: A mixture of sugar and sulphur can be separated by Options:
  A) dissolution in water, evapouration and filtration
  B) filtration, evaporation and dissolution in water
  C) dissolution in water, filtration and evaporation
  D) evaporation, dissolution in water and filtration
  Show Answer
  The correct answer is C .
• Question 145: The principal constituent of natural gas is Options:
  A) methane
  B) ethane
  C) propane
  D) Butane
  Show Answer
  The correct answer is A .
• Question 146: the vapour density of a gas may be defined as Options:
  A) the mass of a unit volume of the gas compared to an equal volume of water vapour
  B) the mass of a unit volume of the gas compared to an equal volume of hydrogen
  C) the mass of a unit volume of the gas compared to an equal volume of oxygen
  D) the mass of a unit volume of the gas minus the vapour pressure of water
  E) two times the relative molecular mass of the gas
  Show Answer
  The correct answer is B .
• Question 147: When hydrogen sulphide and sulphur dioxide are each passed in turn into a solution of potassium dichromate? Options:
  A) both gases change the colour of the solution from yellow to colourless
  B) both gases causes sulphur to be deposited
  C) only hydrogen sulphide decolourizes the solution
  D) only sulphur dioxide deposits sulphur
  E) only hydrogen sulphide deposits sulphur
  Show Answer
  The correct answer is E .
• Question 148: The isomers of C₃H₈O ARE Options:
  A) 1 - propanol and 2 - propanol
  B) 1 - propanol and 1 - propanol
  C) 2 - propanol and 2 - propanone
  D) 2 - propanol and 1 - propanol
  Show Answer
  The correct answer is A .
• Question 149: Some products of destructive distillation of coal are Options:
  A) carbon (IV) oxide and ethanoic acid
  B) trioxocarbonate (IV) acid and methanoic acid
  C) producer gas and water gas
  D) coke and ammonia liquor
  Show Answer
  The correct answer is D .
• Question 150: An example of oxidation - reduction enzyme is Options:
  A) amylase
  B) protease
  C) lipase
  D) dehydrogenase
  Show Answer
  The correct answer is D .