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 981:

  

  The solubility curve of a solid X (molecular mass = 160) is as show above 1,000 cm³ of a saturated solution of X at 80^oC. The weight of X crystalized out would be

  Options:
  A) 10 g
  B) 12 g
  C) 14 g
  D) 16 g
  E) 18 g
  Show Answer
  The correct answer is D .
• Question 982: The shape of ammonia molecules is Options:
  A) trigonal planar
  B) octahedral
  C) square planar
  D) tetrahedral
  Show Answer
  The correct answer is A .
• Question 983:

  According to the kinetic theory of gases, the pressure exerted by a gas is due to

  Options:
  A) The vibrations of gas particles.
  B) The weight of the gas particles
  C) The attractive forces between gas particles
  D) The collisions of gas particles with the container walls
  Show Answer
  The correct answer is D .
• Question 984: When copper (ii) sulphate solution is treated with excess ammonium hydroxide, a precipitate is first formed, and then this dissolves to give a deep blue solution. This deep blue solution is a Options:
  A) Cu(OH)₂
  B) CuSo₄.5H₂O
  C) (NH₄)₂SO₄
  D) Cu(NH₃)₄(OH)₂
  E) CuSO₄.(NH₄)₂SO₄.2H₂O
  Show Answer
  The correct answer is E .
• Question 985: Which of the following statement is false? Options:
  A) Acids react with some metals, liberating hydrogen
  B) Acids react with carbonates, liberating carbondioxide
  C) Acids conduct electricity and are decomposed by the current, liberating hydrogen at the anode
  D) Acids have a sour taste
  E) Acids change the colour of indicators
  Show Answer
  The correct answer is C .
• Question 986: Which of the following electrodes is used in electrolysis of bauxite (Al₂O₃) in molten cryolite? Options:
  A) Steel electrodes
  B) Carbon electrodes
  C) Mercury electrodes
  D) Carbon anode and steel cathode
  E) Carbon cathode and stell anode
  Show Answer
  The correct answer is B .
• Question 987: The repeating unit in natural rubber is Options:
  A) alkyne
  B) isoprene
  C) n-propene
  D) peoprene
  Show Answer
  The correct answer is B .
• Question 988: Ordinary glass is manufactured from silica, CaCO₃ and Options:
  A) Na₂CO₃
  B) K₂CO₃
  C) K₂SO₄
  D) NaHCO₃
  Show Answer
  The correct answer is A .
• Question 989: The atom of an element X is represented as _z^yX. The basic chemical properties of X depends on the value of Options:
  A) Y
  B) Z
  C) Y - Z
  D) Z - Y
  Show Answer
  The correct answer is B .
• Question 990:

  The gas which causes global warming is?

  Options:
  A) O${}_2$
  B) CO${}_2$
  C) N${}_2$
  D) He
  Show Answer
  The correct answer is B .