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 1421:

  Which of the following compounds will form a solution if exposed to air?

  Options:
  A) Na₂CO₃.10H₂O
  B) NaNO₃
  C) CuSO₄
  D) CaCl₂
  E) NaSO₄.10H₂O
  Show Answer
  The correct answer is D .
• Question 1422: An endothermic reaction is one during which heat is.....and can be represented by the symbol.... which of the following combinations can be used accurately to complete the above definition? Options:
  A) liberated, -$\mathrm{\Delta }$H
  B) liberated, +$\mathrm{\Delta }$H
  C) absorbed, -$\mathrm{\Delta }$H
  D) absorbed, +$\mathrm{\Delta }$H
  E) absorbed, +$\mathrm{\Delta }$G
  Show Answer
  The correct answer is D .
• Question 1423: In which of the following is the entropy change positive? Options:
  A) H₂O_(I) → H₂O_(g)
  B) Cu²⁺_{(aq) + Fe(s)} → Fe⁽²⁺⁾ + Cu_(s)
  C) N_2(g) + 3H_2(g) → 2NH_3(g)
  D) 2HCI_(s) → H_2(g) + CI_2(g)
  Show Answer
  The correct answer is A .
• Question 1424: Which of the following is used to hasten the ripening of fruit? Options:
  A) Ethene
  B) Ethanol
  C) Ethyne
  D) Ethane
  Show Answer
  The correct answer is A .
• Question 1425:

  ME + nF -----> pG + qH 

  In the equation shown, the equilibrium constant is given by?

  Options:
  A) $\frac{[E{]}^m[F]}{[G{]}^p[H{]}^q}$
  B) $\frac{[E][F]}{[G][H]}$
  C) $\frac{[G{]}^p[H{]}^p}{[E{]}^m[F{]}^n}$
  D) $\frac{[G][H]}{[E][F]}$
  Show Answer
  The correct answer is C .
• Question 1426: The weakest attractive force that can be observed between two molecules is Options:
  A) ionic
  B) covalent
  C) coordinate covalent
  D) van der Waals
  Show Answer
  The correct answer is D .
• Question 1427:

  A blue litmus paper turns red when dipped into a solution. What does this indicate about the solution?

  Options:
  A) The solution is basic
  B) The solution is neutral
  C) The solution is acidic
  D) The litmus paper is faulty
  Show Answer
  The correct answer is C .
• Question 1428: The boiling point of water, ethanol, toluene and butan-2-ol are 373.0k, 351.3k, 383.6k and 372.5k respectively. Which liquid has the highest vapour pressure at 323.0k? Options:
  A) water
  B) toluene
  C) ethanol
  D) butan-2-ol
  E) none
  Show Answer
  The correct answer is C .
• Question 1429: The set of pollutants that is most likely to be produced when petrol is accidentally spilled on plastic materials and ignited is Options:
  A) CO, CO² and SO²
  B) CO, HCL and SO²
  C) CO, CO² and HCL
  D) SO², CO² and HCL
  Show Answer
  The correct answer is B .
• Question 1430: The solubilites of different solutes in a given solvent can be compared by Options:
  A) plotting their solubility curves on separete axes
  B) plotting their solubility curves on the same axes
  C) plotting some of the solubility curves on the x-axis and others on the y-axis
  D) plotting their solubility curves on the x-axis only
  Show Answer
  The correct answer is B .