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 541: The mass number of an atom is? Options:
  A) the number of electrons in the atom
  B) the number of protons in the nucleus of the atom
  C) the number of neutrons in the nucleus of the atom
  D) the sum of numbers of electrons and protons inthe atom
  E) the sum of numbers of proton and neutrons in the nucleus of the atom
  Show Answer
  The correct answer is E .
• Question 542:

  

  The I.U.P.A.C name for the compound

  Options:
  A) 2-methyl-3-pentene
  B) 4-methyl-2-pentane
  C) 2-methyl-2-pentene
  D) 4-methylpent-2-ene
  E) 2-methyl-3-pentane
  Show Answer
  The correct answer is D .
• Question 543: How many lone pairs of electron are there on the central atom of the H₂O molecules? Options:
  A) 1
  B) 2
  C) 3
  D) 4
  Show Answer
  The correct answer is B .
• Question 544: Complete oxidation of propan -1- ol gives? Options:
  A) propanal
  B) propan-2-al
  C) propan-1-one
  D) propanoic acid
  Show Answer
  The correct answer is D .
• Question 545: The cracking process is very important in the petroleum industry because it. Options:
  A) gives purer products
  B) yields more lubricants
  C) yields more engine fuels
  D) yields more asphalt
  E) yields more candle wax
  Show Answer
  The correct answer is C .
• Question 546:

  

  The graph above demonstrate the effect of

  Options:
  A) surface area on the rate of reaction
  B) catalyst on the rate of reaction
  C) pressure on the rate reaction
  D) concentration on the rate of reaction
  Show Answer
  The correct answer is A .
• Question 547: Detergents are manufacture with strength hydrocarbon chains is to make them Options:
  A) soluble
  B) biodegradable
  C) cheaper
  D) foamy
  Show Answer
  The correct answer is B .
• Question 548: Sieving is a technique used to separate mixture containing solid particles of Options:
  A) small sizes
  B) large sizes
  C) differents sizes
  D) the same sizes
  Show Answer
  The correct answer is C .
• Question 549:

  Deliquescent substances are also?

  Options:
  A) efflorescent
  B) anhydrous
  C) hygroscopic
  D) insoluble
  Show Answer
  The correct answer is C .
• Question 550: CHCl₃ + Cl₂ → HCl + CCl₄. The reaction above is an example of? Options:
  A) an addition reaction
  B) a substitution reaction
  C) a chlorination reaction
  D) a condensation reaction
  Show Answer
  The correct answer is B .