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 711: During the electrolysis of a salt of a metal M, a current of 0.5 A flows from for 32 minutes 10 seconds and deposits 0.325 g of M, What is the charge of the metal ion?(M = 65, If = 96,500 C per mole of electron) Options:
  A) 1
  B) 2
  C) 3
  D) 4
  Show Answer
  The correct answer is B .
• Question 712: 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 713:

  Which of the following will give a precipitate with an aqueous solution of copper (I) chloride?

  Options:
  A) But-2-ene
  B) But-1-ene
  C) But-2-yne
  D) But-1-yne
  Show Answer
  The correct answer is D .
• Question 714: H ₂O _(g) + C _(s) → H_2(g) + CO_(g)The oxidizing agent in the reaction above is Options:
  A) CO_(g)
  B) C_(s)
  C) H₂O_(g)
  D) H_(2)(g)
  Show Answer
  The correct answer is C .
• Question 715:

  Two equal bulbs, one containing ammonia and the other nitrogen are opened mouth-to-mouth to each other at room temperature. The entropy in the mixture of gases is likely to

  Options:
  A) remain unchanged
  B) increase
  C) decrease
  D) change
  Show Answer
  The correct answer is B .
• Question 716:

  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 717: In the course of purifying water for town supply the water is passed through large settlings tanks, containing sodium aluminate (III) to remove Options:
  A) large particles
  B) germs
  C) fine particles
  D) odour
  Show Answer
  The correct answer is A .
• Question 718: If the rate law obtained for a given reaction is rate = k(X)ⁿ (Y)^m, what is the overall order of the reaction? Options:
  A) nm
  B) n/m
  C) n + m
  D) n - m
  Show Answer
  The correct answer is C .
• Question 719: Which of the following groups of physical properties increases from left to right of the periodic table? i. Ionization energy ii. Atomic radius iii. Electronegativity iv. Electro affinity Options:
  A) i and ii
  B) i, ii and iii
  C) iii and iv
  D) i, ii, iii and iv
  Show Answer
  The correct answer is C .
• Question 720: The leachate of a certain ash is used in local soap because it contain Options:
  A) sodium chloride and potassium hydroxide
  B) sodium hydroxide
  C) potassium hydroxide
  D) soluble carbonates and hydrogen carbonate
  Show Answer
  The correct answer is B .