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 1771: The iron (III) oxide impurity in bauxite can be removed by? Options:
  A) Fractional crystallization in acid solution
  B) dissolution in sodium hydroxide and filtration
  C) extraction with concentrated ammonia and reprecipitation
  D) electroysis of molten mixture
  Show Answer
  The correct answer is B .
• Question 1772: 28.8 cm³ of nitrogen at 15°C is cooled to O°C at constant pressure, the new volume of nitrogen is? Options:
  A) 17.4 cm³
  B) 14.7 cm³
  C) 27.3 cm³
  D) 31.7 cm³
  Show Answer
  The correct answer is C .
• Question 1773: A phenomenon where an element exist in different forms in the same physical state is known as Options:
  A) isomerism
  B) amorphism
  C) allotropy
  D) isotopy
  Show Answer
  The correct answer is C .
• Question 1774:

  An element Z contains 80% of ${}_8^{16}$Z and 20% of ${}_8^{18}$Z. Its relative atomic mass is

  Options:
  A) 16.2
  B) 17.6
  C) 16.0
  D) 16.4
  Show Answer
  The correct answer is D .
• Question 1775: 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 1776: The ores that can be concentrated by flotation are Options:
  A) nitride ores
  B) sulphide ores
  C) oxide ores
  D) non-metals
  Show Answer
  The correct answer is B .
• Question 1777: One mole of hydrocarbon contains 6g of hydrogen. If the molecular weight is 54, the hydrocarbon is an? Options:
  A) alkanone
  B) alkane
  C) alkene
  D) alkyne
  Show Answer
  The correct answer is D .
• Question 1778: A noble gas with a high power of fog penetration used in aerodrome beacons is Options:
  A) krpton
  B) argon
  C) helium
  D) neon
  Show Answer
  The correct answer is D .
• Question 1779:

  At 2.0 atm pressure, the volume of a gas is 4.0 L. If the pressure is reduced to 1.0 atm while keeping the temperature constant, what will be the new volume of the gas?

  Options:
  A) 2.0 L
  B) 6.0 L
  C) 8.0 L
  D) 4.0 L
  Show Answer
  The correct answer is C .
• Question 1780: An acid is said to be weak if? Options:
  A) its ions are so completely dissociated that they easily drift apart
  B) the acid is not corrosive
  C) the acid has low specific gravity
  D) its ions move very slowly when in solution
  E) its ions are incompletely dissociated
  Show Answer
  The correct answer is E .