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 1381: The main impurity in iron ore during the extraction of iron is Options:
  A) Silicon (IV) oxide
  B) Carbon (IV) oxide
  C) Calcium trioxosilicate
  D) Sulphur (II) oxide
  Show Answer
  The correct answer is A .
• Question 1382:

  Elements P, Q, R, S have 6, 11, 15, 17 electrons respectively, therefore,

  Options:
  A) P will form an electrovalent bond with R
  B) Q will form a covalent bond with S
  C) R will form an electrovalent bond with S
  D) Q will form an electrovalent bond with S
  E) Q will form a covalent bond with R
  Show Answer
  The correct answer is D .
• Question 1383:

  What type of reaction is involved in the formation of alkanols from alkenes?

  Options:
  A) Elimination reaction
  B) Redox reaction
  C) Substitution reaction
  D) Addition reaction
  Show Answer
  The correct answer is D .
• Question 1384:

  

  Which of the following compounds is a secondary alkanol?

  Options:
  A) A
  B) B
  C) C
  D) D
  Show Answer
  The correct answer is A .
• Question 1385: A gas X diffuses twice as fast as gas Y. if the relative molecular mass of X is 32, calculate the relative molecular mass of Y. Options:
  A) 128
  B) 8
  C) 16
  D) 64
  Show Answer
  The correct answer is A .
• Question 1386: An acid and its conjugate base Options:
  A) can neutralise each other to form a salt
  B) differ only by a proton
  C) differ only by the opposite charges they carry
  D) are always neutral substances
  Show Answer
  The correct answer is B .
• Question 1387:

  By what amount must the temperature of 200cm${}^3$ of Nitrogen at 27°C be increased to double the pressure if the final volume is 150cm${}^3$ (Assume ideality)

  Options:
  A) 150°C
  B) 177°C
  C) 75°C
  D) 120°C
  Show Answer
  The correct answer is B .
• Question 1388:

  An unknown organic compound X has a relative molecular mass of 180. It is a colourless crystaline solid, readily soluble in water. X contains the elements C, H and O in the atomic ratio 1: 2:1. The compound has a sweet teste and melts on heating. In the presence of yeast and in the absence of air, X is converted to compound Y and a colourless gas. Compound Y reacts with sodium metal to produce a gas Z which gives a 'pop' sound with a glowing splint. Y also reacts with ethanoic acid to give a sweet smelling compound W.

  Compound W is

  Options:
  A) a soap
  B) an oil
  C) an alkane
  D) an ester
  E) sucrose
  Show Answer
  The correct answer is D .
• Question 1389: Which of the following compounds is composed of Al, Si, O and H? Options:
  A) Epson salt
  B) Limestone
  C) Clay
  D) Urea
  Show Answer
  The correct answer is C .
• Question 1390: Which of the following physical properties decreases across the Periodic Table? Options:
  A) Ionization potenial
  B) Electron affinity
  C) Electronegativity
  D) Atomic radius
  Show Answer
  The correct answer is D .