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 531:

  The volume of 2.5 moles of oxygen at s.t.p is

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

  Options:
  A) 50.0 dm³
  B) 84.0 dm³
  C) 28.0 dm³
  D) 56.0 dm³
  Show Answer
  The correct answer is D .
• Question 532:

  How many grams of H₂SO₄ are necessary for the preparation of 0.175 dm³ of M 6.00 M H₂SO₄?

  (S = 32.06, O = 16.00 H = 1.00)

  Options:
  A) 206.0 g
  B) 103.0 g
  C) 98.1 g
  D) 51.5 g
  Show Answer
  The correct answer is B .
• Question 533: Due to the unstable nature of ethyne, it is stored by dissolving in Options:
  A) ethane-1,2-diol
  B) propanol
  C) ethanoic acid
  D) propanone
  Show Answer
  The correct answer is D .
• Question 534: The oxidation state of manganese in potassium permanganate is Options:
  A) +7
  B) +5
  C) +3
  D) +2
  E) +1
  Show Answer
  The correct answer is A .
• Question 535:

  At room temperature and standard pressure, chlorine gas is in which state of matter?

  Options:
  A) Plasma
  B) Solid
  C) Liquid
  D) Gas
  Show Answer
  The correct answer is D .
• Question 536: 1.0 dm³ of distilled water was used to wash 2.0g of a precipitate of AgCl. If the solubility product of AgCl is 2.0 * 10^-10mol²dm^-6, what quantity of silver was lost in the process? Options:
  A) 2.029 * 10^-3mol dm^-3
  B) 1.414 * 10^-3mol dm^-3
  C) 2.029 * 10^-5mol dm^-3
  D) 1.414 * 10^-5mol dm^-3
  Show Answer
  The correct answer is D .
• Question 537: what is the pH of 0.00lmoldm³ solution of sodium hydroxide Options:
  A) 14
  B) 13
  C) 12
  D) 11
  Show Answer
  The correct answer is D .
• Question 538: When a pressure cooker is half filled with water, and heated to boiling point, then the pressure inside the cooker will? Options:
  A) decrease, since only a fraction of the water molecules has changed to vapour
  B) remain constant, because the total number of water molecules has not changed
  C) increase, because the water molecules can now reach every part of the sealed tube
  D) decrease, since water boils under reduced pressure
  E) increase, because the water vapour molecules now strike the walls of the tube more frequently because of their increased velocity
  Show Answer
  The correct answer is E .
• Question 539: Two organic compounds K and L were treated with a few drops of Fehling's solutions respectively . K formed a brick-red precipitate while L, remains unaffected. The compound K is an Options:
  A) alkanol
  B) alkane
  C) alkanal
  D) alkanone
  Show Answer
  The correct answer is C .
• Question 540: A particle that contains 9 protons, 10 neutrons and 10 electrons is a Options:
  A) negative ion
  B) positive ion
  C) neutral atom of non-metal
  D) neutral atom of a metal
  Show Answer
  The correct answer is A .