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 901:

  Hydrogen diffused through a porous plug

  Options:
  A) thrice as fast as oxygen
  B) at the same speed as oxygen
  C) four times as fast as oxygen
  D) twice as fast as oxygen
  Show Answer
  The correct answer is C .
• Question 902:

  In troposphere, the two types of pollutants are?

  Options:
  A) Gaseous and particulate pollutants
  B) Carbon and metallic pollutants
  C) Natural and man-made pollutants
  D) Sulphuric and nitrogenous pollutants
  Show Answer
  The correct answer is A .
• Question 903: Water is poured over a white solid and a colourless neutral gas is evolved which burns with a sooty flame. The white solid is? Options:
  A) calcium
  B) calcium oxide
  C) calcium carbide
  D) sodium peroxide
  E) sodium sulphate
  Show Answer
  The correct answer is C .
• Question 904:

  Cu²⁺_(aq) + 4NH_3(g) ↔ [Cu(NH₃)₄]²⁺_(aq)

  In the reaction above, what is the effect of precipitating Cu²⁺_(aq) as CuS_(s)?

  Options:
  A) NH_3(g) concentration will decrease
  B) more NH_3(g)
  C) The equilibrium will shift to the right
  D) There will be no effect
  Show Answer
  The correct answer is C .
• Question 905:

  Which of the following is a common laboratory indicator for bases?

  Options:
  A) Methyl orange
  B) Phenolphthalein
  C) Bromothymol blue
  D) Litmus
  Show Answer
  The correct answer is B .
• Question 906: An oxidation state of or in K2CrO7 Options:
  A) 7
  B) 6
  C) 5
  D) 4
  Show Answer
  The correct answer is B .
• Question 907: An isotope has an atomic number of 15 and a mass number of 31. The number of proton it contains is Options:
  A) 16
  B) 15
  C) 31
  D) 46
  Show Answer
  The correct answer is B .
• Question 908: Electronic configuration of an elements 13x in the subsidiary energy level is Options:
  A) $1s^{2}2s^{2}2p^{6}3s^{2}3p^1$
  B) $1s^{2}2s^{2}2p^{4}3p^{1}3s^1$
  C) $1s^{2}2s^{2}2p^{6}3s^{2}3p^3$
  D) $1s^{1}2s^{2}2p^{6}3s^{2}3p^4$
  Show Answer
  The correct answer is A .
• Question 909: A compound commonly used for sterilization and preservation of specimens and food is Options:
  A) ethanol
  B) benzene
  C) ether
  D) ammonia
  Show Answer
  The correct answer is A .
• Question 910:

  According to Charles' law, the volume of a gas becomes zero at

  Options:
  A) 0°C
  B) -100°C
  C) -273°C
  D) -373°C
  Show Answer
  The correct answer is C .