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 31:

  According to the kinetic theory of gases, the pressure exerted by a gas is due to

  Options:
  A) The vibrations of gas particles.
  B) The weight of the gas particles
  C) The attractive forces between gas particles
  D) The collisions of gas particles with the container walls
  Show Answer
  The correct answer is D .
• Question 32:

  An example of a polysaccharide is?

  Options:
  A) Dextrose
  B) Mannose
  C) Glucose
  D) Starch
  Show Answer
  The correct answer is D .
• Question 33: An organic compound contains 60% carbon, 13.3% hydrogen and 26.7% oxygen. Calculate the empirical formula
  rn(C=12,H =1, O=16) Options:
  A) C ₅H ₁₂O
  B) C ₃H ₈O
  C) C ₆H ₁₃O ₂
  D) C ₄H ₉O
  Show Answer
  The correct answer is B .
• Question 34: An oxidation state of or in K2CrO7 Options:
  A) 7
  B) 6
  C) 5
  D) 4
  Show Answer
  The correct answer is B .
• Question 35: How many unpaired electron are in the p-orbitals of a fluorine atom? Options:
  A) 3
  B) $0$
  C) 1
  D) 2
  Show Answer
  The correct answer is C .
• Question 36: At 25^oC and 1atm, a gas occupies a volume of 1.50dm³. What volume will it occupy at 100^oC and 1atm? Options:
  A) 1.88 dm³
  B) 6.00 dm³
  C) 18.80 dm³
  D) 18.80 dm³
  E) 60.00dm³
  Show Answer
  The correct answer is A .
• Question 37: The nitrogen gas obtained by burning an excess of phosphorus in air has a density higher than the nitrogen from nitrogen compounds because the nitrogen from air is contaminated with? Options:
  A) some unburnt phosporus
  B) P₂O₅ vapour
  C) some oxygen
  D) rare gases
  E) carbondioxide
  Show Answer
  The correct answer is D .
• Question 38: A catalyst increase the rate of a chemical reaction by providing a path that Options:
  A) raise the activiation energy
  B) increase the temperature
  C) lowers the activation energy
  D) increase the concentration
  Show Answer
  The correct answer is C .
• Question 39: If the elements X and Y have atomic numbers 11 and 17 respectively, what type of bond can they form? Options:
  A) Dative
  B) Covalent
  C) Lonic
  D) Metallic
  Show Answer
  The correct answer is C .
• Question 40: The arrangement of particles in crystal lattices can be studied using Options:
  A) X-rays
  B) $\beta$-rays
  C) $\alpha$-rays
  D) $\gamma$-rays
  Show Answer
  The correct answer is A .