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 1771:

  Helium is used in observation of ballons because it is?

  Options:
  A) Light and combustible
  B) light and non-combustible
  C) heavy and combustible
  D) heavy and non-combustible
  Show Answer
  The correct answer is B .
• Question 1772:

  Which functional group is present in alkanals?

  Options:
  A) Carbonyl group (C=O)
  B) Hydroxyl group (-OH)
  C) Alkyl group (-R)
  D) Carboxyl group (-COOH)
  Show Answer
  The correct answer is A .
• Question 1773:

  

  In the above set up substances X and Y are respectively

  Options:
  A) lime water copper (ll) tetraoxosulphate (lV)
  B) potassium trioxocarbonate and alkaline pyrogallol
  C) potassium hydroxide and alkaline pyrogallol
  D) potassium trioxocarbonate (lV) and concentrated tetraoxosulphate (IV) acid
  Show Answer
  The correct answer is C .
• Question 1774: Equal moles of ethyne and hydrogen iodide react to give Options:
  A) CH₂ = CH₂
  B) CH₂ - CHI
  C) CH₃ - CI
  D) CH₂ = CHI
  Show Answer
  The correct answer is D .
• Question 1775:

  Calculate the percentage composition of oxygen in calcium trioxocarbonate(IV) [Ca=40, C=12, O=16]

  Options:
  A) 16
  B) 48
  C) 40
  D) 12
  Show Answer
  The correct answer is B .
• Question 1776: Metalliods are also referred to as Options:
  A) semi-metals
  B) metals
  C) colliods
  D) non-metals
  Show Answer
  The correct answer is A .
• Question 1777:

  Which of the following reactions would be expected to have the highest entropy change?

  Options:
  A) Liquid → Gas
  B) Solid → Liquid
  C) Gas → Liquid
  D) Gas → Solid
  Show Answer
  The correct answer is A .
• Question 1778: Metals of the first transition series have special properties which are different from those of groups I and II elements because they have partially filled Options:
  A) s orbitals
  B) p orbitals
  C) d orbitals
  D) f orbitals
  Show Answer
  The correct answer is C .
• Question 1779:

  

  The above orbital diagram shown the electronic configuration of

  Options:
  A) chlorine
  B) nitrogen
  C) calcium
  D) neon
  Show Answer
  The correct answer is B .
• Question 1780: Which of the following is arranged in order of increasing electronegativity? Options:
  A) Chlorine, aluminium, magnesium, phosphorus, sodium
  B) sodium, magnesium, aluminium, phosphorus, chlorine
  C) Chlorine, phosphorus, phosphorous, aluminium, magnesium, sodium
  D) Sodium, chlorine, phosphorus, magnesium, aluminium
  Show Answer
  The correct answer is B .