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 391:

  n monosaccharide $\underset{Q}{\stackrel{P}{\rightleftharpoons }}$ polysaccharide -n water.

  In the process above, P and Q respectively represent

  Options:
  A) Condensation and hydrolysis
  B) Fermentation and condensation
  C) Polymerization and hydrolysis
  D) Polymerization and condensation
  Show Answer
  The correct answer is A .
• Question 392: Cu₂S_(s) + O2(g) = 2CU_(s) + SO2_2(g) Options:
  A) +1 to 0
  B) 0 to +2
  C) +2 to +1
  D) 0 to +1
  Show Answer
  The correct answer is A .
• Question 393:

  According to the Kinetic Theory an increase in temperature causes the kinetic energy of particles to

  Options:
  A) decrease
  B) increase
  C) be zero
  D) remain constant
  Show Answer
  The correct answer is B .
• Question 394:

  Soaps clean surfaces on the principlebased on?

  Options:
  A) viscosity
  B) floatation
  C) elasticity
  D) surface tension
  Show Answer
  The correct answer is D .
• Question 395: Which of the following is a deliquescent compound? Options:
  A) Na₂CO₃
  B) CaCl₂
  C) CuO
  D) Na₂CO₃.10H₂O
  Show Answer
  The correct answer is B .
• Question 396:

  A 'breath test' used by traffic police to check drunken driving uses?

  Options:
  A) Tumeric on filter paper
  B) Silica gel coated with saliva nitrate
  C) Potassium permanganate-sulphuric acid
  D) Potassium dichromatic-sulphuric acid
  Show Answer
  The correct answer is D .
• Question 397: The property which makes alcohol soluble in water is the Options:
  A) boiling point
  B) hydrogen bonding
  C) ionic character
  D) covalent nature
  Show Answer
  The correct answer is B .
• Question 398:

  Elements X and Y have electronic configurations 1s${}^2$2s${}^2$2p${}^4$ and 1s${}^2$2s${}^2$2p${}^6$3s${}^2$3p${}^1$ respectively. When they combine, the formula of the compound formed is

  Options:
  A) XY
  B) X${}_2$Y
  C) Y${}_2$X${}_3$
  D) X${}_2$Y${}_3$
  Show Answer
  The correct answer is C .
• Question 399:

  What happens to the value of the equilibrium constant (Kc) for a reaction if the reaction is reversed?

  Options:
  A) It becomes zero
  B) It becomes negative
  C) It remains the same
  D) It becomes the reciprocal of the original value
  Show Answer
  The correct answer is D .
• Question 400: The reaction that takes place in Daniell cell is Options:
  A) direct combination
  B) redox
  C) double decomposition
  D) neutralization
  Show Answer
  The correct answer is B .