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 11: Which of the following substances is the most abundant in the universe? Options:
  A) Carbon
  B) Air
  C) Water
  D) Oxygen
  E) Hydrogen
  Show Answer
  The correct answer is E .
• Question 12:

  N₂O_4(aq) $\rightleftharpoons$ 2NO_2(g) $△$H = +ve

  In the reaction above, an increase in temperature will

  Options:
  A) Increase the reactant production
  B) Increase the value of the equilibrium constant
  C) Shift the equilibrium to the left
  D) Decrease the value of the equilibrium constant
  Show Answer
  The correct answer is B .
• Question 13:

  How many moles of limestone will be required to produce 5.6g of CaO?

  [Ca = 40, C = 12, O= 16]

  Options:
  A) 0.20 mol
  B) 0.10 mol
  C) 1.12 mol
  D) 0.56 mol
  Show Answer
  The correct answer is B .
• Question 14:

  A given amount of gas occupies 10.0dm5 at 4atm and 273°C. The number of moles of the gas present is [Molar volume of gas at s.t.p = 22.4dm${}^3$]

  Options:
  A) 0.89 mol
  B) 1.90 mol
  C) 3.80 mol
  D) 5.70 mol
  Show Answer
  The correct answer is A .
• Question 15:

  Calculate the mass of chlorine gas which occupies a volume of 1.12dm³ at s.t.p

  [Cl = 35.5, molar volume of gas at s.t.p = 22.4 dm³

  Options:
  A) 15.50 g
  B) 7.10 g
  C) 3.55 g
  D) 1.80 g
  Show Answer
  The correct answer is C .
• Question 16:

  A few drop of conc HCL are added to about 10cm${}^3$ of a solution of PH 3.4. The PH of the resulting mixture is?

  Options:
  A) less than 3.4
  B) greater than 3.4
  C) unaltered
  D) the same as that of the pure water
  Show Answer
  The correct answer is A .
• Question 17:

  

  The compound above contains

  Options:
  A) Sp ³ hybridized carbon atoms only
  B) Sp ² hybridized carbon atoms only
  C) Sp ³ and Sp hybirdized carbon atoms
  D) Sp ³ and Sp ²
  Show Answer
  The correct answer is D .
• Question 18:

  Which separation technique is used to separate different pigments in a mixture based on their affinity for a stationary phase and a mobile phase?

  Options:
  A) Chromatography
  B) Filtration
  C) Decantation
  D) Distillation
  Show Answer
  The correct answer is A .
• Question 19: A mixture of common salt, ammonium chloride and barium sulphate can best be separated by Options:
  A) addition of water followed by filtration then sublimation
  B) addition of water followed by sublimation then filtration
  C) sublimation followed by addition of water then filtration
  D) fractional distillation
  E) fractional crystallization
  Show Answer
  The correct answer is C .
• Question 20:

  Given that 15.00 cm³ of H₂

  SO₄ was required to completely neutralize 25.00 cm³ of 0.125 mol dm^-3 NaOH, calculate the molar concentration of the acid solution:

  Options:
  A) 0.925 mol dm^-3
  B) 0.156mol dm^-3
  C) 0.104 mol dm^-3
  D) 0.023 mol dm^-3
  Show Answer
  The correct answer is C .