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 2151: (1 /(2) N_2(g) + (1) / (2)O_2(g) → NO_(g) ∆H° 89 KJ mol^-. If the entropy change for the reaction above at 25°C is 11.8 J mol^-, calculate the change in free energy. ∆G°, for the reaction at 25°C? Options:
  A) 88.71 KJ
  B) 85.48 KJ
  C) -204.00 KJ
  D) -3427.40 KJ
  Show Answer
  The correct answer is D .
• Question 2152:

  The pollutant usually presents in a city which generates its electricity from coal?

  Options:
  A) fog
  B) carbon(ii)oxide
  C) smog
  D) sulphur(iv)oxide
  Show Answer
  The correct answer is D .
• Question 2153: An example of a strong electrolyte is? Options:
  A) ethyl acetate
  B) ethanol
  C) glucose
  D) sodium formate
  E) formic acid
  Show Answer
  The correct answer is D .
• Question 2154: The most abundant element on the earth's crust is Options:
  A) nitrogen
  B) hydrogen
  C) oxygen
  D) flourine
  Show Answer
  The correct answer is C .
• Question 2155:

  An organic compound X has the following properties:
  I. It is not miscible with water.
  ll. It has boiling point of 77^oC.
  lll. It has a sweet odour.
  IV. lt is insoluble in sodium hydrogen carbonate solution.
  V lt does not decolourize bromine water.
  X is therefore

  Options:
  A) methane
  B) ethanoic acid
  C) ethene
  D) ethyl ethanoate
  E) carbon tetrachloride
  Show Answer
  The correct answer is D .
• Question 2156: Which of the following statements is true of sulphur (IV) oxide? Options:
  A) It forms tetraoxosulphate (VI) acid with water
  B) It is an odourless gas
  C) It is an acid hybride
  D) It forms white precipitate with acidified barium chloride
  Show Answer
  The correct answer is C .
• Question 2157:

  A concentrated solution containing H⁺, Cu²⁺, OH^- and Cl^- was electrolyzed using platinum electrodes.

  The ion that will be discharged at the cathode is

  Options:
  A) Cu²⁺
  B) Cl^-
  C) H⁺
  D) OH^-
  Show Answer
  The correct answer is A .
• Question 2158: The air pollutant unknown in nature is Options:
  A) NO
  B) CO
  C) HCHO
  D) DDT
  Show Answer
  The correct answer is D .
• Question 2159: Which of the following physical properties decreases down a group in the periodic table? Options:
  A) Atomic radius
  B) Ionic radius
  C) Electropositivity
  D) Electronegativity
  Show Answer
  The correct answer is B .
• Question 2160: The property used in the industrial preparation of nitrogen and oxygen from air is Options:
  A) rate of diffusion
  B) density
  C) boiling point
  D) solubility
  Show Answer
  The correct answer is C .