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 1931:

  The dehydration of CH${}_3$CH${}_2$CH${}_2$CH${}_2$OH will give?

  Options:
  A) HC≡CCH${}_2$CH${}_3$
  B) CH${}_2$≡CH${}_2$CH${}_3$
  C) CH${}_3$C≡CCH${}_3$
  D) CH${}_3$CH=CHCH${}_3$
  Show Answer
  The correct answer is D .
• Question 1932: Calculate the mass, in kilograms, of magnesium produced by the electrolysis of magnesium (II) chloride in a cell operating for 24 hours at 500 amperes. Options:
  A) 2.7
  B) 5.4
  C) 10.8
  D) 21.7
  Show Answer
  The correct answer is B .
• Question 1933: Hardness of water is caused by the presence of ions of Options:
  A) magnesium and silver
  B) cacium and magnesium
  C) sodium and potassium
  D) calcium and sodium
  Show Answer
  The correct answer is B .
• Question 1934: If an equilibrium reaction has ΔH > 0, the reaction will proceed favourably in the forward direction at Options:
  A) High temperature
  B) Any temperature
  C) Low temperature
  D) Minimum temperature
  Show Answer
  The correct answer is A .
• Question 1935: Sodium carbonate crystals on exposure to a dry atmosphere change to a white powder. This phenomenon is known as? Options:
  A) deliquescence
  B) hygroscopy
  C) oxidation
  D) efforescence
  E) sublimation
  Show Answer
  The correct answer is D .
• Question 1936: Detergents have the general formula? Options:
  A) R(CH₂)_nOH
  B) RSO₃^-Na⁺
  C) RSO^-₂Na⁺
  D) RSO₂H
  Show Answer
  The correct answer is B .
• Question 1937: Which of the following compounds is used as a gaseous fuel? Options:
  A) CH₃ -CH₂ -CHO₂ -COOH
  B) CH₃ -C = CH
  C) CH₃ -CH₂ -CH₂ -CH₃
  D) CH₂ -CH₂ -CH₃
  Show Answer
  The correct answer is C .
• Question 1938:

  

  Select the right answer from the structure above.Which of the following compounds represents the polymerization product of ethyne?

  Options:
  A) A
  B) B
  C) C
  D) D
  Show Answer
  The correct answer is A .
• Question 1939:

  The number of molecules of Carbon(iv)Oxide produced when 10.0g of CaCO${}_3$ is treated with 0.2dm${}^3$ of 1 Mole of HCL in the equation

  CaCO${}_3$ + 2HCL $\to$ CaCl${}_2$  + H${}_2$ O + CO${}_2$  , is ?

  Options:
  A) 1.00 X 10${}^{23}$
  B) 6.02 X 10${}^{23}$
  C) 6.02 X 10${}^{22}$
  D) 6.02 X 10${}^{24}$
  Show Answer
  The correct answer is C .
• Question 1940:

  

  In the diagram above, curve X represents the energy profile for a homogeneous gaseous reaction. Which of the following conditions would produce curve Y for the same reaction?

  Options:
  A) Increase in temperature
  B) Increase in the concentration of a reactant
  C) Addition of a catalyst
  D) Increase in pressure
  Show Answer
  The correct answer is C .