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 371: The hybridization of the carbon atom in ethyne is Options:
  A) sp ⁴
  B) sp ³
  C) sp²
  D) sp
  E) s
  Show Answer
  The correct answer is D .
• Question 372: Elements P, Q, R, S have 6, 11, 15, 17 electrons respectively, therefore, Options:
  A) P will form an electrovalent bond with R
  B) Q will form a covalent bond with S
  C) R will form an electrovalent bond with S
  D) Q will form an electrovalent bond with S
  E) Q will form a covalent bond with R
  Show Answer
  The correct answer is D .
• Question 373:

  The shapes of water, ammonia, carbon (iv) oxide and methane are respectively

  Options:
  A) linear, tetrahedral, angular and pyramidal
  B) angular, pyramidal, linear and tetrahedral
  C) pyramidal, linear, tetrahedral and angular
  D) tetrahedral, angular, pyramidal and linear
  Show Answer
  The correct answer is B .
• Question 374: Carbohydrates are large molecules with the molecular formula C _x (H₂O)_y. In which of the following pairs is x not equal to y? Options:
  A) glucose and starch
  B) maltose and starch
  C) sucrose and fructose
  D) maltose and starch
  Show Answer
  The correct answer is A .
• Question 375: Addition of dilute hydrochloride acid to an aqueous solution of a crystalline salt yield a yellow precipitate and a gas which turned dichromate paper green. The crystalline salt was probably? Options:
  A) Na₂SO₄
  B) Na₂S
  C) Na₂S₂O₃.5H₂O
  D) Na₂CO₃
  E) NaHCO₃
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  The correct answer is C .
• Question 376: Which of the following is physical change? Options:
  A) Burning kerosene
  B) Freezing ice cream
  C) Exposing white phosphorus
  D) Dissolving calcium in water
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  The correct answer is B .
• Question 377: the vapour density of a gas may be defined as Options:
  A) the mass of a unit volume of the gas compared to an equal volume of water vapour
  B) the mass of a unit volume of the gas compared to an equal volume of hydrogen
  C) the mass of a unit volume of the gas compared to an equal volume of oxygen
  D) the mass of a unit volume of the gas minus the vapour pressure of water
  E) two times the relative molecular mass of the gas
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  The correct answer is B .
• Question 378:

  A synthetic rubber is obtained from the polymerization of

  Options:
  A) neoprene
  B) isoprene
  C) butandiene
  D) propylene
  Show Answer
  The correct answer is B .
• Question 379: CO_g + H₂O_g $\to$ _2g + H_2g $\mathrm{\Delta }$H = -4100J. Which of the following factors favour the formation of hydrogen in the above reaction? i. high pressure. ii. low pressure iii. high temperature iv. use of excess steam Options:
  A) i, iii and iv
  B) iii only
  C) ii, iii and i
  D) iv only
  Show Answer
  The correct answer is D .
• Question 380:

  In the reaction

  C + 2HNO₃ → CO₂ + NO₂ + NO + H₂O nitric acid is acting as?

  Options:
  A) a reducing agent
  B) a nitrating agent
  C) an oxidizing agent
  D) a catalytic agent
  E) a neutralizing agent
  Show Answer
  The correct answer is C .