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 771: The elements that belong to the third period of periodic table are Options:
  A) Li, Be, Al and D
  B) Na, P, O and Cl
  C) B, C, N, and O
  D) N2, Mg, S and Ar
  Show Answer
  The correct answer is D .
• Question 772: The mass of silver deposited when a current of 10A is passed through a solution of silver salt for 4830s is – (Ag = 108 F = 96500(mol^-1) Options:
  A) 54.0g
  B) 27.0g
  C) 13.5g
  D) 108.0g
  Show Answer
  The correct answer is A .
• Question 773:

  At 25^o and zymase as catalyst,

  C₆H₁₂₆ → 2C₂H₅OH + 2CO₂ + energy

  The reaction above represented by the equation above is useful in the production of

  Options:
  A) propanol
  B) butanol
  C) methanol
  D) ethanol
  Show Answer
  The correct answer is D .
• Question 774:

  2KClO3(g) MNO3→ 2KCl(s) + 3O2(g)

  The importance of the catalyst in the reaction above is that

  Options:
  A) heating may not be required before the reaction takes place
  B) the reaction is controllable even at a high temperature
  C) the reaction produces large quantity of oxygen
  D) the reaction takes place more rapidly at a lower temperature
  Show Answer
  The correct answer is D .
• Question 775: The residual solids from the fractional distillation of petroleum are used as Options:
  A) coatings of pipes
  B) raw materials for the cracking process
  C) fuel for the driving tractors
  D) fuel for jet engines
  Show Answer
  The correct answer is A .
• Question 776:

  

  In the diagram above, X is the ``

  Options:
  A) enthalpy
  B) enthalpy change
  C) activation energy
  D) activated complex
  Show Answer
  The correct answer is B .
• Question 777:

  An element having the atomic number 17 will resemble which of the following elements having atomic number as given below?

  Options:
  A) 33
  B) 35
  C) 18
  D) 19
  Show Answer
  The correct answer is B .
• Question 778:

  A gaseous metallic chloride MCl consists of 20.22% of M by mass. The formula of the chloride is?

  [ M = 27, Cl = 35.5]

  Options:
  A) MCl
  B) MCl${}_2$
  C) MCl${}_3$
  D) M${}_2$Cl${}_6$
  Show Answer
  The correct answer is C .
• Question 779:

  The IUPAC name for CH${}_3$CH${}_2$COOCH${}_2$CH${}_3$ is

  Options:
  A) methylpropanoate
  B) ethylethanoate
  C) ethylpropanoate
  D) methylethanoate
  Show Answer
  The correct answer is C .
• Question 780: When copper powder is heated with concentrated sulphuric acid, the gas produced is? Options:
  A) hydrogen sulphide
  B) sulphur dioxide
  C) sulphur trioxide
  D) hydrogen pentasulphide
  E) sulphur pentoxide
  Show Answer
  The correct answer is B .