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 561: A side effect of soft water is that Options:
  A) it gives offensive taste
  B) excess calcium is precipitated
  C) it attacks lead contained in pipes
  D) it encourage the growth of bacteria
  Show Answer
  The correct answer is C .
• Question 562:

  A colourless organic compound X was burnt in excess air to give two colourless and odourless gases, Y and Z, as products. X does not decolorize blue bromine vapour, Y turns lime milky while Z gives a blue colour with copper (ll) tetraoxosulphate (IV).

  Compound X is?

  Options:
  A) an alkene
  B) an alkane
  C) an alkyne
  D) tetrachloromethane
  E) dichloromethane
  Show Answer
  The correct answer is B .
• Question 563:

  A compound contains 40.0% carbon, 6.7% hydrogen and 53.3% oxygen. If the molar mass of the compound is 180. Find the molecular formula.

  [H = 1, C = 12, O = 16]

  Options:
  A) C${}_3$H${}_6$O${}_3$
  B) C${}_6$H${}_6$O${}_3$
  C) C${}_6$H${}_{12}$O${}_6$
  D) CH${}_2$O
  Show Answer
  The correct answer is C .
• Question 564:

  In the reaction N₂(g) + O(g) ↔ 2NO(g) produced an increase in the total pressure will?

  Options:
  A) cause less nitrogen to be produced in the equilibrium mixture
  B) cause less nitric oxide to be produced in the equilibrium mixture
  C) cause more nitric oxide to be produced in the equilibrium mixture
  D) cause more oxygen to be produced in the equilibrium mixture
  E) have no effect
  Show Answer
  The correct answer is E .
• Question 565:

  

  The diagram represents

  Options:
  A) A spontaneous reaction
  B) An exothermic reaction
  C) A non-spontaneous
  D) An endothermic reaction
  Show Answer
  The correct answer is C .
• Question 566: Smoke consist of? Options:
  A) solid particles dispersed in liquid
  B) solid or liquid particles dispersed in gas
  C) gas or liquid particles dispersed inliquid
  D) liquid particles dispersed inliquid
  Show Answer
  The correct answer is B .
• Question 567: Fluorine does not occur in the free state in nature because Options:
  A) it is a poisonous gas
  B) it belongs to the halogen family
  C) it is inert
  D) of its high reactivity
  Show Answer
  The correct answer is D .
• Question 568: When sodium is added to ethanol, the products are? Options:
  A) sodium hydroxide and water
  B) sodium hydroxide and hydrogen
  C) sodium ethoxide and water
  D) sodium ethoxide and hydrogen
  Show Answer
  The correct answer is D .
• Question 569: The efficiency of petrol as a fuel in high-compression internal combustion engines improves with an increase in the amount of? Options:
  A) branched chain alkanes
  B) straight chain alkanes
  C) cycloalkanes
  D) halogenated hydrocarbons
  Show Answer
  The correct answer is A .
• Question 570: A hydrated salt of formula MSO₄.xH₂ O CONTAINS 45.3% by mass of water of crystalisation. Calculate the value of x [M = 56, S = 32, O = 16, H = 1 ] Options:
  A) 3
  B) 5
  C) 7
  D) 10
  Show Answer
  The correct answer is C .