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 711: Mortar is NOT used for under-water construction because Options:
  A) it hardens by lose of water
  B) its hardening doe not depend upon evaporation
  C) it requires concrete to harden
  D) it will be washed away by the flow of water
  Show Answer
  The correct answer is A .
• Question 712:

  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 713:

  The nucleusof a hydrogen atom consist of a?

  Options:
  A) 1 proton only
  B) 1 proton, 2 neutron
  C) 1 neutron only
  D) 1 electron only
  Show Answer
  The correct answer is A .
• Question 714: In the laboratory preparation of chlorine from concentrated hydrochloric acid in the presence of potassuim tetraoxomanganate(VII) the produced is dried by passing it through Options:
  A) Concentrated tetraoxosulphate (VI) acid
  B) Anhydrous calcium chloride
  C) Calcium oxide
  D) Sodium hydroxide
  Show Answer
  The correct answer is A .
• Question 715: If the rate of diffusion of oxygen gas is taken as 1, what will be rated of diffusion of methane whose relative molar mass is 16? Options:
  A) 2.0
  B) 1.8
  C) 1.4
  D) 1.0
  E) 0.5
  Show Answer
  The correct answer is C .
• Question 716:

  An element X has two isotopes, ²⁰₁₀X and ²⁰₁₀X, present in the ratio 1:3. The relative atomic mass of X would be?

  Options:
  A) 20.5
  B) 21.0
  C) 21.5
  D) 22.0
  E) 22.5
  Show Answer
  The correct answer is C .
• Question 717: When sodium dioxonitrate (lll) (NaNO₂) dissolves in water, ∆H is positive. The process of dissolution is Options:
  A) exothermic
  B) endothermic
  C) isothermal
  D) isomeric
  E) hygroscopic
  Show Answer
  The correct answer is B .
• Question 718:

  

  What is the IUPAC name for the compound?

  Options:
  A) 1-chloro-2-methylprop-2,3-ene
  B) 1-chloro-2-methylprop-2-ene
  C) 3-chloro-2-methylprop-1-ene
  D) 3-chloro-2methylprop-1,2-ene
  Show Answer
  The correct answer is C .
• Question 719: An endothermic reaction is one during which heat is.....and can be represented by the symbol.... which of the following combinations can be used accurately to complete the above definition? Options:
  A) liberated, -$\mathrm{\Delta }$H
  B) liberated, +$\mathrm{\Delta }$H
  C) absorbed, -$\mathrm{\Delta }$H
  D) absorbed, +$\mathrm{\Delta }$H
  E) absorbed, +$\mathrm{\Delta }$G
  Show Answer
  The correct answer is D .
• Question 720: The solubility curve shows the variation of solute concentration with Options:
  A) volume
  B) temperature
  C) vapour
  D) pressure
  E) weight
  Show Answer
  The correct answer is A .