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:

  GAS	CO${}_2$	N${}_2$	O${}_2$
  % BY VOLUME	4	72	24

  The above table shows the compositions of the atmosphere of planet X. Which of these gases are present inhigherpercentages on earth?

  Options:
  A) CO${}_2$ and O${}_2$
  B) N${}_2$ and CO${}_2$
  C) CO${}_2$, O${}_2$ and N${}_2$
  D) O${}_2$ and N${}_2$
  Show Answer
  The correct answer is D .
• Question 292:

  On the basis of the electrochemical series, which of these ions will show the greater tendency to be discharged at the cathode in an electrolytic cell

  Options:
  A) cu${}^{2+}$
  B) sn${}^{2+}$
  C) fe${}^{2+}$
  D) zn${}^{2+}$
  Show Answer
  The correct answer is A .
• Question 293: Ammonium chloride can be separated from its mixture with common salt by Options:
  A) Distillation
  B) Evaporation
  C) Decantation
  D) Sublimation
  Show Answer
  The correct answer is D .
• Question 294: Metals of the first transition series have special properties which are different from those of groups I and II elements because they have partially filled Options:
  A) s orbitals
  B) p orbitals
  C) d orbitals
  D) f orbitals
  Show Answer
  The correct answer is C .
• Question 295:

  56.00cm³ of a gas at S.T.P. weighed 0.11g. What is the vapour density of the gas?
  [Molar volume of a gas at S.T.P = 22.4dm³]

  Options:
  A) 11.00
  B) 22.00
  C) 33.00
  D) 44.00
  Show Answer
  The correct answer is B .
• Question 296: Two metallic ions associated with hard water are Options:
  A) copper and zinc
  B) magnesium and silver
  C) calcium and magnesium
  D) potassium and tin
  E) sodium and lead
  Show Answer
  The correct answer is C .
• Question 297:

  A metallic oxide which reacts with both HCl and NaOH to give salt and water only can be classified as __________.

  Options:
  A) an acidic oxide
  B) a basic oxide
  C) a neutral oxide
  D) an amphoteric oxide
  Show Answer
  The correct answer is D .
• Question 298: Copper (II) tetraoxosulphate (VI) solution is electrolyzed using carbon electrodes. Which of the following are produced at the anode and cathode respectively ? Options:
  A) Copper and oxygen
  B) Oxygen and copper
  C) Hydrogen and copper
  D) Copper and hydrogen
  Show Answer
  The correct answer is B .
• Question 299: In the industrial production of H₂ is removed by (solution) Options:
  A) washing under pressure
  B) drying over phosphorus (V) oxide
  C) passing the mixture to the limewater
  D) using ammonical copper (I) chlorine
  Show Answer
  The correct answer is A .
• Question 300: What volume of 11.0 M hydrochloric acid must be dilute to obtain 1 dm³ of 0.05 M acid? Options:
  A) 0.05 dm³
  B) 0.10 dm³
  C) 0.55 dm³
  D) 11.0 dm³
  Show Answer
  The correct answer is A .