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 1261: Consider the following exothermic reaction 2SO₂(g) + O₂(g) = 2SO₃ (g) . If the temperature of the reaction is reduced from 800_oC to 500_oC, and no other change takes place, then Options:
  A) the reaction rate increases
  B) concentration of SO₃ decreases
  C) concentration of SO₃ increases
  D) SO₂ gas becomes unreactive
  E) O₂ gas becomes unreactive
  Show Answer
  The correct answer is C .
• Question 1262: Which of the following substances are all made by the process of polymerization? Options:
  A) Nylon and soap
  B) Ethanoic acid margarine and ethanol
  C) Nylon and artificial rubber
  D) Soap and butane
  E) Margarine and nylon
  Show Answer
  The correct answer is C .
• Question 1263:

  What happens when alkanoic acids react with alcohols in the presence of an acid catalyst?

  Options:
  A) Saponification
  B) Esterification
  C) Polymerization
  D) Hydrolysis
  Show Answer
  The correct answer is B .
• Question 1264: Hydrogen is used in oxy-hydrogen flames for melting metals because it Options:
  A) evolves a lot of heat when burnt
  B) combines explosively with oxygen
  C) is a very light gas
  D) is a rocket fuel
  Show Answer
  The correct answer is A .
• Question 1265: Cu₂S_(s) + O2(g) = 2CU_(s) + SO2_2(g) Options:
  A) +1 to 0
  B) 0 to +2
  C) +2 to +1
  D) 0 to +1
  Show Answer
  The correct answer is A .
• Question 1266:

  Which of the following metals is the most essential in the regulation of blood volume, blood pressure and osmotic equilibrium?

  Options:
  A) Zinc
  B) Manganese
  C) Sodium
  D) Iron
  Show Answer
  The correct answer is C .
• Question 1267: Which of the following sets of metals dissolves in dilute HCl? Options:
  A) Fe, Sn and Cu
  B) Mg, Fe and Cu
  C) Mg, Sn and Fe
  D) Cu, Mg and Sn
  Show Answer
  The correct answer is C .
• Question 1268: Alkaonic acids have low volatility compared with alkanols because they? Options:
  A) are more polar than alkaonls
  B) have two oxygen atoms while alkanols have one
  C) form hydrogen bonds while alkanols do not
  D) form two hydrogen bonds while alkanols form one
  Show Answer
  The correct answer is D .
• Question 1269:

  A gaseous metallic chloride MCl_x consists of 20.22% of M by mass. The formula of the chloride is

  [M = 27, Cl = 35.5]

  Options:
  A) MCl
  B) MCl₂
  C) MCl₃
  D) M₂Cl₆
  Show Answer
  The correct answer is C .
• Question 1270: Some properties of chemical substances are mentioned below... i. sour taste ii. slippery touch iii. yields alkaline gas with ammonium salt iv. has pH less than 7 v. turns phenolphthalein pink.Which of the above are NOT typical properties of alkalis? Options:
  A) i, iv and v
  B) iv and v
  C) i and iv
  D) ii and v
  E) ii, iii and iv
  Show Answer
  The correct answer is C .