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 1071: The acid used in electrolysis of water is dilute Options:
  A) HNO₃
  B) CH₃COOH
  C) H₂SO₄
  D) HCl
  Show Answer
  The correct answer is C .
• Question 1072: The reaction of zinc with copper (ll) ions in aqueous solution can be represented as follows: Cu ²⁺(aq) +Zn (s) → Cu(s) + Zn ²⁺(aq).Which of the following is the most complete description of this reaction? Options:
  A) Cpper (ll) ions are being reduced
  B) Zinc is being oxidized.
  C) Copper (ll) ions and zinc are being reduced
  D) copper (ll) ions and zinc are being oxidized
  E) copper(ll) ions are being reduced and zinc oxidized
  Show Answer
  The correct answer is E .
• Question 1073: Which of the following ions is a pollutant in drinking water even in trace amounts? Options:
  A) Ca²⁺
  B) Hg²⁺
  C) Mg²⁺
  D) Fe²⁺
  Show Answer
  The correct answer is B .
• Question 1074: In which of the following are water molecules in the most disorderly arrangement? Options:
  A) Ice at -10°C
  B) Ice at 0°C
  C) Water at 100°C
  D) Steam at 100°C
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  The correct answer is D .
• Question 1075:

  16.8 g of sodium hydrogen trioxocarbonate (IV) is completely decomposed by heat. Calculate the volume of carbon(IV) oxide given off s.t.p

  [Na 23, C = 12, O = 16, H = 1, Molar volume of a gas at s.t.p = 22.4 dm³]

  Options:
  A) 22.40 dm³
  B) 11.20 dm³
  C) 2.24 dm³
  D) 1.12 dm³
  Show Answer
  The correct answer is C .
• Question 1076: In the production of soap, concentrated sodium chloride solution is added to Options:
  A) Increase the solubility of soap
  B) Decrease the solubility of the soap
  C) Saponify the soap
  D) Emulsify the soap
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  The correct answer is B .
• Question 1077:

  

  The name of the compound above is

  Options:
  A) acetic acid
  B) propanal
  C) propanol
  D) ethanoic acid
  E) propanoic acid
  Show Answer
  The correct answer is E .
• Question 1078: The pressure of 100cm³ of oxygen at 35^oC is 750mmHg. What will be the volume of gas if the pressure is reduced to 100mmHg without changing the temperature? Options:
  A) 650 cm³
  B) 850 cm³
  C) 580 cm³
  D) 750 cm³
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  The correct answer is D .
• Question 1079: 10cm³ of hydrogen fluoride gas react with 5cm³ of dinitrogen difluoride gas (N²F₂) to form 10₃ of a single gas. Which of the following is the most likely equation of the reaction? Options:
  A) HF + N₂F₂ $\to$ N₂HF₃
  B) 2HF + N₂F₂ $\to$ 2NHF₂
  C) 2HF + N₂F₂ $\to$ N₂H₂F₃
  D) HF + 2N₂F₂ $\to$ N₄HF₂
  Show Answer
  The correct answer is B .
• Question 1080: An iron ore is known to contain 70.0% Fe₂O₃. The obtain from 80kg of the ore is?(Fe = 56, O = 16) Options:
  A) 35.0 kg
  B) 39.2 kg
  C) 70.0 kg
  D) 78.4 kg
  Show Answer
  The correct answer is B .