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 401:

  An element, X, forms a volatile hydride XH₃ with a vapour density of 17.0. The relative atomic mass of X is?

  (H = 1)

  Options:
  A) 34.0
  B) 31.0
  C) 20.0
  D) 14.0
  Show Answer
  The correct answer is B .
• Question 402: In countries where the temperature fall below 273k, salt always spilled on the ray road in order to Options:
  A) increase the making point office
  B) increase the density of the ice
  C) make the ice impure
  D) rinse the making point of the ice
  Show Answer
  The correct answer is A .
• Question 403: The boiling point of water, ethanol, toluene and butan-2-ol are 373.0k, 351.3k, 383.6k and 372.5k respectively. Which liquid has the highest vapour pressure at 323.0k? Options:
  A) water
  B) toluene
  C) ethanol
  D) butan-2-ol
  E) none
  Show Answer
  The correct answer is C .
• Question 404:

  

  Use the options above to answer this question. Which is the structural formula for pent-2-enoic acid?

  Options:
  A) A
  B) B
  C) C
  D) D
  Show Answer
  The correct answer is C .
• Question 405:

  The sub-atomic particles located in the nucleus of an atomare?

  Options:
  A) neutron and proton
  B) proton and electron
  C) proton and ions
  D) neutron and electron
  Show Answer
  The correct answer is A .
• Question 406: Clothes should be properly rinsed with water after bleaching because Options:
  A) the bleach decolourizes the clothes
  B) chlorine reacts with fabrics during bleaching
  C) the clothes are sterilized during bleaching
  D) hydrogen chloride solution is produced during bleaching
  Show Answer
  The correct answer is D .
• Question 407:

  The refreshing and characteristic taste of soda water and other soft drinks is as a result of the presence of

  Options:
  A) carbon(IV)oxide
  B) carbon(ll)oxide
  C) soda
  D) glucose
  Show Answer
  The correct answer is A .
• Question 408: Which of the following will change when a catalyst is added to a chemical reaction? Options:
  A) The activation energy
  B) The potential energy of the reactants
  C) The heat of the reaction
  D) the potential energy of the product
  Show Answer
  The correct answer is A .
• Question 409: How many cations will be produced from a solution of potassium aluminium tetraoxosulphate (VI)? Options:
  A) 3
  B) 4
  C) 1
  D) 2
  Show Answer
  The correct answer is D .
• Question 410: Atomicity of ozone is Options:
  A) 1
  B) 2
  C) 3
  D) 4
  Show Answer
  The correct answer is C .