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 1: The densities of two gases, X and Y are 0.5gdm^-3 and 2.0gdm^-3 respectively. What is the rate of diffusion of X relative to Y? Options:
  A) 0.1
  B) 0.5
  C) 2.0
  D) 4.0
  Show Answer
  The correct answer is C .
• Question 2: 25 cm³ of 0.02 M KOH neutralized 0.03 g of a monobasic organic acid having the general formula C_nH_{2n + 1} COOH. The molecular formula of the acid is?(C = 12, H = 1, O = 16) Options:
  A) HCOOH
  B) C₂H₅COOH
  C) CH₃COOH
  D) C₃H₇COOH
  Show Answer
  The correct answer is C .
• Question 3:

  The sulphide that is commonly used in coating electric fluorescent tubes is?

  Options:
  A) iron(ii)Sulphide
  B) tin(ii)sulphide
  C) Zinc Sulphide
  D) lead(iv) Sulphide
  Show Answer
  The correct answer is C .
• Question 4: A particle that contains a protons, 10 neutrons and 10 electrons is Options:
  A) positive ion
  B) neutral atom of a metal
  C) neutral atom of a non-metal
  D) negative ion
  Show Answer
  The correct answer is D .
• Question 5:

  

  The tabulated results below were obtained by titration 10.0 cm³ of water with soup. The titration was repeated with the same sample of water after boiling. The ratio of permanent to temporary hardness is

  Options:
  A) 1.5
  B) 1.4
  C) 4.1
  D) 5.1
  Show Answer
  The correct answer is C .
• Question 6:

  Which of the following changes is physical?

  Options:
  A) Adding iron filing to aerated water
  B) Adding sodium metal to water
  C) Cooling a solution of Iron (II) sulphate to obtain the hydrated salt
  D) Cooling water to obtain ice
  E) Burning the domestic gas (Utilgas) for cooking
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  The correct answer is D .
• Question 7: The solvent used for removing grease stain is Options:
  A) turpentine
  B) ammonia solution
  C) ethanol
  D) solution of borax in water
  Show Answer
  The correct answer is B .
• Question 8:

  What is the mass percentage of carbon (C) in methane (CH4)? (The molar mass of carbon is approximately 12 g/mol.)

  Options:
  A) 25%
  B) 12%
  C) 75%
  D) 50%
  Show Answer
  The correct answer is C .
• Question 9: In the chemical reaction A + B $\to$ C + D, more of D is formed? Options:
  A) if the concentrated of A is reduced
  B) if the concentrated of B is reduced
  C) if the concentrated of C is reduced
  D) if the concentration of C is increased
  E) if D is continuously removed from the reaction mixture
  Show Answer
  The correct answer is E .
• Question 10: If a gas occupies a container of volume 146 cm³ at 18°C and 0.97`atm, its volume 146cm³ at s.t.p is? Options:
  A) 133
  B) 146
  C) 266
  D) 292
  Show Answer
  The correct answer is A .