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 361:

  C₃H₅ - COH₃ =CH₂

  The IUPAC nomenclature of the structure above is

  Options:
  A) 3-methybut-3-ene
  B) 2-methylbut-1-ene
  C) 2-ethylprop-1-ene
  D) 2-methylbut-2-ene
  Show Answer
  The correct answer is B .
• Question 362: In which of the following is the entropy change positive? Options:
  A) H₂O_(I) → H₂O_(g)
  B) Cu²⁺_{(aq) + Fe(s)} → Fe⁽²⁺⁾ + Cu_(s)
  C) N_2(g) + 3H_2(g) → 2NH_3(g)
  D) 2HCI_(s) → H_2(g) + CI_2(g)
  Show Answer
  The correct answer is A .
• Question 363:

  2H${}_2$ + O${}_2$ 2H${}_2$O

  From the equationabove, calculate the volume of unreacted oxygen gas if a mixture of 50cm${}^3$ of hydroden and 75cm${}^3$ of oxygen are involved

  Options:
  A) 85cm${}^3$
  B) 50cm${}^3$
  C) 125cm${}^3$
  D) 55cm${}^3$
  Show Answer
  The correct answer is B .
• Question 364: Which of the following is a solvent for perfumes? Options:
  A) C₅H₁₂
  B) C₄H₆
  C) CH₃COOH
  D) C₂H₅OH
  Show Answer
  The correct answer is D .
• Question 365: The fraction of crude oil used as jet fuel is Options:
  A) refinery gas
  B) diesel oil
  C) kerosine
  D) gasoline
  Show Answer
  The correct answer is C .
• Question 366: The products of the reaction between dilute sulphuric acid and sodium thiosulphate crystals are? Options:
  A) Na₂SO₄ + SO₂ + O₂ + H₂O
  B) Na₂SO₃ + SO₃ + O₂ + H₂O
  C) Na₂SO₄ + SO₂ + S + H₂O
  D) Na₂SO₄ + SO₃ + S + H₂O
  E) Na₂SO₄ + SO₂ + H₂O only
  Show Answer
  The correct answer is C .
• Question 367:

  Calculate the percentage by mass of nitrogen in calcium trioxonitrate (V).
  [Ca = 40, N = 14, O = 16]

  Options:
  A) 8.5%
  B) 13.1%
  C) 17.1%
  D) 27.6%
  Show Answer
  The correct answer is C .
• Question 368: The formula for ethyl butanoate is Options:
  A) C₃H₇COOC₂H₅
  B) C₂H₅COOC₃H₇
  C) C₄H₉COOC₂H₅
  D) C₂H₅COOC₄H₉
  Show Answer
  The correct answer is A .
• Question 369:

  

  The compound above is the product of the oxidation of

  Options:
  A) 2-methlbutan-2-ol
  B) 2-methylbutan -1- ol
  C) 2, 3-dimethylprop 1-ol
  D) Pentan -2- ol
  Show Answer
  The correct answer is B .
• Question 370: In the purification of town water supply, alum is used principally to? Options:
  A) kill bacteria
  B) control the pH of water
  C) improve the taste of the water
  D) coagulate small pasrticles of mud
  Show Answer
  The correct answer is D .