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 381: Which of the following statements is true of sulphur (IV) oxide? Options:
  A) It forms tetraoxosulphate (VI) acid with water
  B) It is an odourless gas
  C) It is an acid hybride
  D) It forms white precipitate with acidified barium chloride
  Show Answer
  The correct answer is C .
• Question 382:

  Suitable reagents for the laboratory preparation nitrogen are

  Options:
  A) sodium dioxonitrate(III) and ammonium chloride
  B) sodium trioxonitrate(V) and ammonium chloride
  C) sodium chloride and ammonium trioxonitrate(V)
  D) sodium chloride and ammonium di-ozonitrate(III)
  Show Answer
  The correct answer is A .
• Question 383: What is the decrease in volume of air when pyrogallol is shaken with 30.00cm³ of air ? Options:
  A) 15.00cm³
  B) 6.30cm³
  C) 0.63cm³
  D) 0.06cm³
  Show Answer
  The correct answer is B .
• Question 384: Which of the following methods can be used to obtain pure water from a mixture of sand, water and methanoic acid? Options:
  A) netralization with NaOHfoolowed by filtration
  B) neutralization with NaOH followed by distillation
  C) fractional distillation
  D) filtration followed by distillation
  Show Answer
  The correct answer is D .
• Question 385: Which of the following raw materials would be required from the smelting of iron ore in a blast furnace? Options:
  A) CaCO ₃
  B) Zn(NO₃)₂
  C) CuSO₄
  D) AICI₃
  E) CaSO₄
  Show Answer
  The correct answer is A .
• Question 386: On exposure to the atmosphere, a hydrated salt loses its water of crystallization to become anhydrous. This phenomenon is referred to as Options:
  A) efflorescence
  B) diliquescence
  C) hygroscopy
  D) hydrolysis
  Show Answer
  The correct answer is A .
• Question 387:

  ME + nF -----> pG + qH 

  In the equation shown, the equilibrium constant is given by?

  Options:
  A) $\frac{[E{]}^m[F]}{[G{]}^p[H{]}^q}$
  B) $\frac{[E][F]}{[G][H]}$
  C) $\frac{[G{]}^p[H{]}^p}{[E{]}^m[F{]}^n}$
  D) $\frac{[G][H]}{[E][F]}$
  Show Answer
  The correct answer is C .
• Question 388: A gas occupies 30.0 dm³ at S.T.P. What volume would it occupy at 91^oC and 380 mm Hg? Options:
  A) 20. 0dm³
  B) 40.0dm³
  C) 60. 0dm³
  D) 80. 0dm³
  E) 100. 0dm³
  Show Answer
  The correct answer is D .
• Question 389: In the preparation of ammonia, which of the following is used as the drying agent? Options:
  A) CaO
  B) CaCI₂
  C) Conc. H₂SO₄
  D) P₂O₅
  E) H₃PO₄
  Show Answer
  The correct answer is A .
• Question 390: In the experiment, which of the following observations would suggest that a solid sample is a mixture? The Options:
  A) solid can be ground to a fine powder
  B) density of the solid is 2.25gdm^-3
  C) solid begins to melt at 573k but is not completely melted until 648k
  D) solid absorbs moisture from the atmosphere and turns into liquid
  E) solid melts at 300k
  Show Answer
  The correct answer is C .