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 11:

  A small quantity of solid ammonium chloride (NH₄Cl) was heated gently in a test tube, the solid gradually disappears to produce two gases. Later, a white cloudy deposit was observed on the cooler part of the test tube. The ammonium chloride is said to have undergone

  Options:
  A) distillation
  B) sublimation
  C) precipitation
  D) evaporation
  E) decomposition
  Show Answer
  The correct answer is B .
• Question 12: A liquid that will dissolve fat is Options:
  A) Hydrochloric acid
  B) Calcium hydroxide
  C) Kerosene
  D) Water
  Show Answer
  The correct answer is B .
• Question 13: Sodium hydroxide (NaOH) pellets are Options:
  A) deliquescent
  B) hygroscopic
  C) efflorescent
  D) hydrated
  E) fluorescent
  Show Answer
  The correct answer is A .
• Question 14:

  

  In the above experiment X is

  Options:
  A) pure nitrogen
  B) a mixture of nitrogen and oxygen
  C) a mixture of nitrogen and carbondioxide
  D) a mixture of oxygen and inert gases
  E) a mixture of nitrogen and inert gases
  Show Answer
  The correct answer is E .
• Question 15: The substance often use for vulcanization of rubber is Options:
  A) chlorine
  B) hydrogen peroxide
  C) sulphur
  D) tetraoxosulphate (IV) acid
  Show Answer
  The correct answer is C .
• Question 16:

  

  Carbon (ll) oxide may be collected as shown above because it

  Options:
  A) is heavier than air
  B) is less dense than air
  C) is insoluble in water
  D) burns in oxygen to form carbon (IV) oxide
  Show Answer
  The correct answer is C .
• Question 17:

  What is the molar mass of water (H2O)?

  Options:
  A) 18 g/mol
  B) 22 g/mol
  C) 16 g/mol
  D) 12 g/mol
  Show Answer
  The correct answer is A .
• Question 18: Which of these solutions will give a white precipitate with a solution of barium chloride acidified with hydrochloric acid? Options:
  A) Sodium trioxocarbonate (IV)
  B) Sodium tetraoxosulphate (IV)
  C) Sodium trioxosulphate (IV)
  D) Sodium sulphide
  Show Answer
  The correct answer is A .
• Question 19: Four elements P,Q, R and S have atomic numbers of 4, 10, 12 and 14 respectively . Which of these electrons is a noble gas? Options:
  A) P
  B) Q
  C) R
  D) S
  Show Answer
  The correct answer is B .
• Question 20:

  Which of the following is a characteristic property of acids?

  Options:
  A) Turn litmus paper blue
  B) Bitter taste
  C) pH value above 7
  D) React with metals to produce hydrogen gas
  Show Answer
  The correct answer is D .