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 861: Which of the following gases contains the least number of atoms at s.t.p? Options:
  A) 1 mole of butane
  B) 3 mole of ozone
  C) 4 mole of chlorine
  D) 7 mole of argon
  Show Answer
  The correct answer is A .
• Question 862:

  NH₃ + H₃O⁺

  → NH₄⁺ + H₂O. It may be deduced from the reaction above that?

  Options:
  A) a redox reaction has occurred
  B) H₃O⁺ acts as an oxidizing agent
  C) H₃O⁺ acts as an acid
  D) water acts as ab acid
  Show Answer
  The correct answer is C .
• Question 863:

  The nucleusof a hydrogen atom consist of a?

  Options:
  A) 1 proton only
  B) 1 proton, 2 neutron
  C) 1 neutron only
  D) 1 electron only
  Show Answer
  The correct answer is A .
• Question 864: Which of the following questions is correct about the periodic table? Options:
  A) The non-metallic properties of the elements tend to decrease across each period
  B) The valence electrons of the elements increase progressively across the period
  C) Elements in the same group have the same numbeer of electron shells
  D) Elements in the same period have the number of valence electrons
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  The correct answer is B .
• Question 865:

  The following non-metal form acidic oxides with oxygen except?

  Options:
  A) phosphorus
  B) sulphur
  C) carbon
  D) chlorine
  Show Answer
  The correct answer is C .
• Question 866: The scale formation in a kinetic used for boiling water is caused by the presence in water of? Options:
  A) calcium sulphate
  B) calcium carbonate
  C) calcium hydrogen carbonate
  D) calcium hydroxide
  E) magnesium sulphate
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  The correct answer is C .
• Question 867:

  Which noble gas is radioactive and is produced as a decay product of uranium and thorium?

  Options:
  A) Argon
  B) Krypton
  C) Radon
  D) Neon
  Show Answer
  The correct answer is C .
• Question 868: Which of the following solutions will give a white precipitate with barium chloride solution and a green flame test? Options:
  A) Na₂SO₄
  B) CuSO₄
  C) CaSO₄
  D) CaCI₂
  E) (NH₄)₂SO₄
  Show Answer
  The correct answer is B .
• Question 869:

  2SO_2(g) + O_2(g) ↔ 2SO_3(g)

  ΔH = -189 kJ mol^-1

  The equilibrium constant for the reaction above is increased by

  Options:
  A) Increasing the temperature of the system
  B) Increase the pressure of the system
  C) The addition of a catalyst to the system
  D) Increasing the surface area of the vessel
  Show Answer
  The correct answer is B .
• Question 870: Which of the following gases contains the highest number of atoms at s.t.p? Options:
  A) 6 moles of neon
  B) 3 moles of oxygen
  C) 2 moles of chlorine
  D) 1 mole of ethane
  Show Answer
  The correct answer is A .