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 351:

  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 352:

  What happens when alkanoic acids react with alcohols in the presence of an acid catalyst?

  Options:
  A) Saponification
  B) Esterification
  C) Polymerization
  D) Hydrolysis
  Show Answer
  The correct answer is B .
• Question 353:

  The sub-atomic particles located in the nucleus of an atomare?

  Options:
  A) neutron and proton
  B) proton and electron
  C) proton and ions
  D) neutron and electron
  Show Answer
  The correct answer is A .
• Question 354: The mixture of gases used in a photographer's flash tube is Options:
  A) argon and krypton
  B) krypton and xenon
  C) helium and argon
  D) argon and xenon
  Show Answer
  The correct answer is B .
• Question 355:

  To what temperature must a gas at 273k be heated in order to double both its volume and pressure?

  Options:
  A) 298K
  B) 546K
  C) 819K
  D) 1092K
  Show Answer
  The correct answer is D .
• Question 356:

  The type of bonding in [Cu(NH${}_3$)${}^4$]${}^{2+}$ is 

  Options:
  A) coordinate
  B) electrovalent
  C) metallic
  D) covalent
  Show Answer
  The correct answer is A .
• Question 357: 0.25 mole of hydrogen chloride was dissolved in distilled water and the volume made up of 0.50 dm³. If 15.0 cm³ of the solution requires 12.50 cm³ of aqueous sodium trioxocarbonate (IV) for neutralization, calculate the concentration of the alkaline solution Options:
  A) 0.30 mol dm³
  B) 0.40 mol dm³
  C) 0.50 mol dm³
  D) 0.60 mol dm³
  Show Answer
  The correct answer is A .
• Question 358:

  At 27°C, 58.5g of sodium chloride is present in 250cm${}^3$ of a solution. The solubility of sodium chloride at this temperature is?

  (molar mass of sodium chloride = 111.0gmol${}^{-1}$)

  Options:
  A) 2.0 moldm${}^{-3}$
  B) 0.25 moldm${}^{-3}$
  C) 1.0 moldm${}^{-3}$
  D) 0.5 moldm${}^{-3}$
  Show Answer
  The correct answer is A .
• Question 359: Polystyrene is widely used as packaging materials for fragile objects during transportation because of its Options:
  A) ligjtness
  B) low density
  C) high density
  D) high compressibility
  Show Answer
  The correct answer is D .
• Question 360: On heating anhydrous iron (ll) sulphate, in addition to producing iron (iii) oxide, which of the following is produced? Options:
  A) SO₂ (g) + FeS (s)
  B) SO₃ (g) +FeS(s)
  C) SO₂ (g) + SO₃(g)
  D) SO₂ (g) + H₂S (g)
  E) SO₃(g) + H₂S(g)
  Show Answer
  The correct answer is C .