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 441: If an atom is represented as ${}_{11}^{23}X$, which of the following deduction is correct? Options:
  A) it contains 12 protonic
  B) it forms a covalent chloride
  C) its atomic number is 23
  D) it is an alkali metal
  Show Answer
  The correct answer is D .
• Question 442: A good drying agent should be Options:
  A) deliquescent
  B) effervescent
  C) hygroscopic
  D) efflorescent
  Show Answer
  The correct answer is C .
• Question 443: Which of the following pollutants is associated with brain damage? Options:
  A) Carbon (ll) oxide
  B) Radioactive fallout
  C) Biodegradable waste
  D) Sulphus (lV) oxide
  Show Answer
  The correct answer is A .
• Question 444: The oxidation state of manganese in potassium permanganate is Options:
  A) +7
  B) +5
  C) +3
  D) +2
  E) +1
  Show Answer
  The correct answer is A .
• Question 445: Which of the following separation processes is most likely to yield high quality ethanol (>95%) from palm wine? Options:
  A) Fractional distillation without a dehydrant
  B) simple distillation with a dehydrant
  C) fractional distillation with a dehydrant
  D) column chromatography
  E) evaporation
  Show Answer
  The correct answer is C .
• Question 446:

  Which of the following methods can be used to remove temporary hardness from water?

  Options:
  A) Boiling
  B) Filtration
  C) sedimentation
  D) Chlorination
  Show Answer
  The correct answer is A .
• Question 447: All these are electromagnetic waves except Options:
  A) White light
  B) Photon
  C) X-ray
  D) Infrared
  Show Answer
  The correct answer is B .
• Question 448: The density of a certain gas is 1.98gdm^-3 at s.t.p. What is the molecular mas of the gas? Options:
  A) 44.0 g
  B) 54.0 g
  C) 26.0 g
  D) 31.0 g
  Show Answer
  The correct answer is A .
• Question 449: In the discovery of protein, the instrument used is Options:
  A) cathode ray tube
  B) glass tube and discharge tube
  C) discharge tube with terminal cathode
  D) discharge tube with central cathode
  Show Answer
  The correct answer is D .
• Question 450:

  The combustion of carbon(ii)oxide in oxygen can be represented by equation.

  2CO + O${}_2$ → 2CO${}_2$

  Calculate the volume of the resulting mixture at the end of the reaction if 50cm${}_3$ of carbon(ii)oxide was exploded in 100cm${}_3$ of oxygen

  Options:
  A) 75cm${}^3$
  B) 125cm${}^3$
  C) 100cm${}^3$
  D) 50cm${}^3$
  Show Answer
  The correct answer is B .