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 1781: Which of the following noble gases is commonly found in the atmosphere? Options:
  A) Xenon
  B) Neon
  C) Helium
  D) Argon
  Show Answer
  The correct answer is D .
• Question 1782:

  Which halogen is a gas at room temperature and is pale yellow in color?

  Options:
  A) Chlorine (Cl)
  B) Fluorine (F)
  C) Iodine (I)
  D) Bromine (Br)
  Show Answer
  The correct answer is B .
• Question 1783:

  N_2(g) + 3H_2(g) ↔ 2NH_3(g) ΔH = -90 kJ

  In the equation above, the yield of ammonia can be decreased by

  Options:
  A) increasing the pressure
  B) removing the ammonia as it is formed
  C) increase the temperature
  D) adding a catalyst
  Show Answer
  The correct answer is C .
• Question 1784: The reddish–brown rust on ion roofing sheets consists of Options:
  A) Fe³ + (H₂O)₆
  B) FeO.H₂O
  C) Fe₂O₃.3H₂O
  D) Fe₃O₄.2H2₂O
  Show Answer
  The correct answer is C .
• Question 1785:

  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 1786: 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 1787: A mixture of common salt, ammonium chloride and barium sulphate can best be separated by Options:
  A) addition of water followed by filtration then sublimation
  B) addition of water followed by sublimation then filtration
  C) sublimation followed by addition of water then filtration
  D) fractional distillation
  E) fractional crystallization
  Show Answer
  The correct answer is C .
• Question 1788: S₂O^2-₃ + I₂ → S₂O₆^2- + 2I^-. In reaction above, the oxidizing agent is? Options:
  A) S₂O₃^2-
  B) I₂
  C) S₄O₆^2-
  D) I^-
  Show Answer
  The correct answer is B .
• Question 1789:

  .....................P....Q.....R......S

  Proton..............13....16....17.....19

  Electron............13....16....17.....19

  Neutron.............14....16....35.....20Which of the four atoms P,q,R and in S in the above data can be described by the following properties relative atomic mass is greater than 30 but less than 40; it has an odd atomic number and forms a unipositive ion in solution?

  Options:
  A) P
  B) Q
  C) R
  D) S
  Show Answer
  The correct answer is D .
• Question 1790: Sugar is separated from its impurities by Options:
  A) precipitation
  B) crystallization
  C) distillation
  D) evaporation
  Show Answer
  The correct answer is B .