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 1031: Which of the following does NOT happen when a zinc rod is introduced into a solution of copper (ll) sulphate? Options:
  A) Electrons flow towards the zinc rod
  B) The zinc rod dissolves
  C) The temperature of the soil changes
  D) The blue colour of the solution gradually disappears
  E) Copper metal is deposited
  Show Answer
  The correct answer is A .
• Question 1032: The products of the thermal decomposition of ammonium trioxonitrate (V) are Options:
  A) NO ₂ and oxygen
  B) NH₃ and oxygen
  C) nitrogen and water
  D) N₂O and water
  Show Answer
  The correct answer is D .
• Question 1033: In the reaction E+F ↔ G+H, the backward reaction is favoured if the concentration of Options:
  A) F is increased
  B) E is increased
  C) E is reduced
  D) G is reduced
  Show Answer
  The correct answer is C .
• Question 1034:

  MnO_4(aq) + 8H⁺_(aq) + Y → Mn²⁺_(aq) + 4H₂O_(l)

  Y in the equation above represents

  Options:
  A) 2e^-
  B) 3e^-
  C) 5e^-
  D) 7e^-
  Show Answer
  The correct answer is C .
• Question 1035:

  10g of a solid is in equilibrium with its own vapour.

  When 1 g of a small amount of solid is added, the vapour pressure?

  Options:
  A) remains the same
  B) drops
  C) increases by 1%
  D) increases by 99%
  Show Answer
  The correct answer is B .
• Question 1036:

  1.1 g of CaCI₂ dissolved in 50 cm³ of water caused a rise in temperature of3.4°C. The heat of reaction, ∆H for CaCI₂ in kj per mole is?

  (Ca = 40, CI = 35.5, specific heat of water is 4.18 jk^-1

  Options:
  A) -71.1
  B) -4.18
  C) +71.1
  D) +111.0
  Show Answer
  The correct answer is A .
• Question 1037: An organic compound decolourized acidified KMnO₄ solution but failed to react with ammoniacal silver nitrate solution. The organic compound is likely to be? Options:
  A) a carbonxylic acid
  B) an alkane
  C) an alkene
  D) an alkyne
  E) an akanone
  Show Answer
  The correct answer is C .
• Question 1038:

  The solubility in mol dm^-3 of 20g of CuSO₄ dissolved in 100g of water at 180^o is

  [Cu = 64, S = 32, O =16]

  Options:
  A) 0.13
  B) 0.25
  C) 1.25
  D) 2.00
  Show Answer
  The correct answer is C .
• Question 1039:

  In the reaction between sodium hydroxide and sulphuric acid solutions, what volume of 0.5 molar sodium hydroxide would exactly neutralise 10cm3 of 1.25 molar sulphuric acid?

  Options:
  A) 5cm${}^3$
  B) 10cm${}^3$
  C) 20cm${}^3$
  D) 50cm${}^3$
  Show Answer
  The correct answer is D .
• Question 1040: X_(g) → X_(g). The type of energy involved in the above transformation is? Options:
  A) ionization energy
  B) sublimation energy
  C) lattice energy
  D) electron affinity
  Show Answer
  The correct answer is D .