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 501:

  Who proposed the planetary model of the atom with electrons orbiting the nucleus?

  Options:
  A) Erwin Schrödinger
  B) Ernest Rutherford
  C) Niels Bohr
  D) J.J. Thomson
  Show Answer
  The correct answer is C .
• Question 502: A chemical reaction which the hydration energy is greater than the lattice energy is referred to as Options:
  A) a spontaneous reaction
  B) an endothermic reaction
  C) an exothermic reaction
  D) a reversible reaction
  Show Answer
  The correct answer is C .
• Question 503: The combustion of ethene, C ₂H ₄, is given by the equation C ₂H ₄ + 30 ₂ → 2CO₂ + 2H₂ O; ∆H = - 1428 KJ. If the molar heats of formation of water and carbon (IV) oxide are - 286 kJ and - 396 kJ respectively, calculate the molar heat of formation of ethene in KJ Options:
  A) - 2792
  B) + 2792
  C) - 64
  D) + 64
  Show Answer
  The correct answer is D .
• Question 504:

  What volume of oxygen is produced from the decomposition of 2 mole of KCIO₃ at s.t.p?

  [Molar volume of a gas at s.t.p = 22.4 dm³]

  Options:
  A) 22.4 dm³
  B) 33.6 dm³
  C) 44.8 dm³
  D) 67.2 dm³
  Show Answer
  The correct answer is D .
• Question 505: A carcinogenic substance is Options:
  A) asbestos dust
  B) sawdust
  C) nitrogen (II) oxide
  D) carbon (II) oxide
  Show Answer
  The correct answer is A .
• Question 506: The normal boiling point of a liquid is defined as Options:
  A) the temperature at which its vapour pressure equals the atmospheric pressure
  B) the temperature at which bubbles begin to form
  C) the temperature at which the vapour pressure equals 1 temperature
  D) the temperature at which the rate of condensation of vapour equals the rate of vaporisation of the liquid
  E) the temperature at which the space above the liquid is saturated
  Show Answer
  The correct answer is C .
• Question 507: 2.85g of an oxide of copper gave 2.52g of copper on reduction and 1.90g of another oxide gave 1.52g of copper on reduction. The data above illustrates the law of? Options:
  A) constant composition
  B) conservation of mass
  C) reciprocal proportions
  D) multiple proportions
  Show Answer
  The correct answer is D .
• Question 508: Ethanol reacts with concentrated tetraoxosulphate (V) acid at a temperature above 170 ^oC to form Options:
  A) ethanone
  B) ethene
  C) ethyne
  D) ethanal
  Show Answer
  The correct answer is B .
• Question 509:

  

  The IUPAC nomenclature of the compound above is

  Options:
  A) 2-ethylpentane
  B) 3,4-dimethylhexane
  C) 2,3-dimethylhexane
  D) 2-ethylhexane
  Show Answer
  The correct answer is B .
• Question 510: If an element X of an atomic number Z and mass number Y is irradiated by an intense concentration of neutrons, the relevant nuclear equation is? Options:
  A) ^y_zX + ¹₀n → ^{y - 1}_{z + 1}X
  B) ^y_zX + ¹₀n → ^{y + 1}_zX
  C) ^y_zX + ¹₀n → ^y_{z + 1}X
  D) ^y_zX + ¹₀n → ^{y + 1}_{z - 1}X
  Show Answer
  The correct answer is B .