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 141:

  Four elements P, Q, R and S have atomic numbers of 4, 10, 12 and 14 respectively. Which of these elements is noble gas? 

  Options:
  A) P
  B) Q
  C) R
  D) S
  Show Answer
  The correct answer is B .
• Question 142: Pollution of underground water by metal ions is very likely in the soil that has high Options:
  A) acidity
  B) alkalinity
  C) chloride content
  D) nitrate content
  Show Answer
  The correct answer is B .
• Question 143: Which of the following acts as both a reducing and an oxidizing agent? Options:
  A) H₂
  B) SO₂
  C) H₂S
  D) C
  Show Answer
  The correct answer is B .
• Question 144: The number of isomers that can be obtained from 04R0 is Options:
  A) 3
  B) 4
  C) 1
  D) 5
  E) 2
  Show Answer
  The correct answer is E .
• Question 145: When iron is exposed to moisture and it rusts, the value of ΔG for the reaction is Options:
  A) neutral
  B) zero
  C) positive
  D) negative
  Show Answer
  The correct answer is D .
• Question 146: A heterogenous mixture can be defined as any mixture Options:
  A) of a solute nd a solvent
  B) whose cmposition is uniform
  C) whose composition is not uniform
  D) formed by solids and liquids
  Show Answer
  The correct answer is C .
• Question 147:

  Na₂CO₃ + 2HCI → 2NaCI + H₂O + CO₂. Using the above equation, what volume of carbondioxide, measured at s.t.p is liberated when 53g of sodium carbonate is dissolved in hydrochloric acid?

  (1 mole of gas occupies 22.4 dm³ at s.t.p)

  (Na = 23, C = 12, O = 16)

  Options:
  A) 44.8 dm³
  B) 11.2 dm³
  C) 100.1 dm³
  D) 3.0 dm³
  E) 22.4 dm³
  Show Answer
  The correct answer is B .
• Question 148: In the reaction of oxygen with hydrogen to produce water, which of the following statements is true? Options:
  A) One atom of hydrogen reacts with two atoms of oxygen to give one molecule of water
  B) Two atoms of hydrogen react with two atoms of oxygen to give two molecules of water
  C) One molecule of oxygen reacts with one molecule of hydrogen to give two molecules of water
  D) One molecule of hydrogen reaccts with two molecules of oxygen to give three molecules of water
  E) One molecule of oxygen reacts with two molecules of hydrogen to give two molecules of water
  Show Answer
  The correct answer is E .
• Question 149: Environmental pollution is worsened by the release from automobile exhausts of Options:
  A) Water vapour
  B) Steam
  C) Smoke
  D) Heavy metals
  Show Answer
  The correct answer is C .
• Question 150:

  L . Evaporation. ll. Sublimation. lll. Diffusion. IV. Brownian motion.

  Which of the above can correctly be listed as evidences for the particulate nature of matter?

  Options:
  A) I and lll only
  B) ll and lV only
  C) l, ll and lll only
  D) l, ll, lll and lV
  Show Answer
  The correct answer is D .