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 431:

  CH₃COOH_(aq) + OH^-_(aq) ↔ CH₃COO^-_(aq) + H₂O_(l)

  In the reaction above ,CH₃COO^-_(aq) is

  Options:
  A) conjugate base
  B) acid
  C) base
  D) conjugate acid
  Show Answer
  The correct answer is A .
• Question 432:

  If the quantity of oxygen occupying 2.76L container at a pressure of 0.825 atm and 300k is reduced by one-half, what is the pressure exerted by the remaining gas?

  Options:
  A) 1.650atm
  B) 0.825atm
  C) 0.413atm
  D) 0.275atm
  Show Answer
  The correct answer is A .
• Question 433:

  Which of the following is a form of calcium carbonate?

  I. limestone
  II. marble
  III. chalk
  Iv. egg-shells

  Options:
  A) I only
  B) I, II and IV
  C) I and II only
  D) I, II, III, and IV
  Show Answer
  The correct answer is D .
• Question 434: Calculate the amount in moles of a gas which occupies 10.5 dm³ at 6 atm and 30^oC [R = 082 atm dm³ K^-1 mol^-1] Options:
  A) 2.536
  B) 1.623
  C) 4.736
  D) 0.394
  Show Answer
  The correct answer is A .
• Question 435:

  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 436: The gas that will form a white precipitate with acidified silver trioxonitrate (v) is Options:
  A) NH₃
  B) SO₂
  C) CO₂
  D) HCL
  Show Answer
  The correct answer is D .
• Question 437: The solution of a sample in a tube will be identified as a chloride if it gives Options:
  A) a white precipitate on addition of AgNO₃ and barium chloride solutions
  B) a white precipiate when acidified with HCI, and then AgNO₃ solution added
  C) a white precipitate when acidified with dilute HNO₃ and then AgNO₃ solution added
  D) a white precipitate when acidified with dilute H₂SO₄ and then barium nitrate solution added
  E) a pungent smell of chlorine gas when dilute HCI and MnO₂ are added
  Show Answer
  The correct answer is C .
• Question 438: The intermediate product formed when ethanol is progressively oxidized to ethanoic acid with potassium heptaoxodichromate (IV) is Options:
  A) butanal
  B) ethanal
  C) methanal
  D) propanal
  Show Answer
  The correct answer is B .
• Question 439: The product formed when propanol is heated over a copper catalyst in the absence of oxygen are Options:
  A) CH₃CH₂CHO and H₂
  B) CH₃CHO and CO₂
  C) CH₃CH₂COOH and H₂
  D) CH₃COOH and CO₂
  Show Answer
  The correct answer is D .
• Question 440: Which of the following is a example of a chemical change? Options:
  A) Dissoultion of salt in water
  B) Rusting of iron
  C) Melting of ice
  D) Separating a mixture by distillation
  Show Answer
  The correct answer is B .