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 291:

  

  In the experiment above, Z can be

  Options:
  A) a solution of sodium dioxonitrate (lll) and ammonium chloride
  B) a solution of lead trioxnitrate (V)
  C) a solution of sodium trioxonitrate (V) and ammonium chloride
  D) concentrated tetraoxosulphate (VI) acid and sodium trioxonitrate (V)
  Show Answer
  The correct answer is C .
• Question 292: Which of the following statements is FALSE? Options:
  A) Copper (ll) ion can be reduced to copper (l) ion by hydrochloric acid and zinc
  B) Sodium metal dissolves in water giving oxygen
  C) Nitrogen is insoluble in water
  D) Carbondioxide is soluble in water
  E) lead has a higher atomic weight than copper
  Show Answer
  The correct answer is B .
• Question 293:

  Which of the following substances is a mixture?

  Options:
  A) Granulated sugar
  B) Seawater
  C) Sodium chloride
  D) Iron filling
  Show Answer
  The correct answer is B .
• Question 294:

  The process by which salt and water reacted in a limited way to form an acid or abase is?

  Options:
  A) Neutral process
  B) Basic acidic process
  C) Hydrolysis
  D) Sublimation
  Show Answer
  The correct answer is C .
• Question 295: Pure solvents are obtained by Options:
  A) Distillation
  B) Condensation
  C) Extraction
  D) Evaporation
  Show Answer
  The correct answer is A .
• Question 296: C_xH_Y + 4O₂ → 3CO₂ + 2H₂O. The hydrocarbon, C_xH_Y, in the reaction above is? Options:
  A) propane
  B) propene
  C) propyne
  D) propanone
  Show Answer
  The correct answer is C .
• Question 297:

  A radioactive nucleus has a half-life of 20 years, starting with 100,000 particles, how many particles will be left exactly at the end of 40 years

  Options:
  A) 75,000 particles
  B) 35,000 particles
  C) 25,000 particles
  D) 50,000 particles
  Show Answer
  The correct answer is C .
• Question 298: Which of the following combination of gases is used for metal welding? i. Oxygen and ethyne, ii. Hydrogen and ethyne, iii. Hydrogen and oxygen, iv. Ethyne, hydrogen and oxygen. Options:
  A) i and ii
  B) ii and iv
  C) i and iii
  D) ii and iv
  Show Answer
  The correct answer is A .
• Question 299: In which of the following reactions is sulphur dioxide acting as an oxidizing agent? Options:
  A) SO ₂ + 2HNO₃ →H₂SO₄ + NO₂ + Heat
  B) 2SO₂ + 2H₂O + O₂→ 2H₂SO₄
  C) SO₂ + 2H₂O + CI₂→ H₂SO₄ + 2HCI
  D) SO₂ + 2H₂S → 3S + 2H₂O
  E) SO₂ + H₂O → H₂SO₃
  Show Answer
  The correct answer is D .
• Question 300: Which of the following relationships between the pressure P, the volume V and the temperature T, represents an ideal gas behaviour? Options:
  A) P $\alpha$ VT
  B) P $\alpha$ T/V
  C) PT $\alpha$ V
  D) PV $\alpha$ I/T
  E) P $\alpha$ V/T
  Show Answer
  The correct answer is B .