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 111: The processes which return carbon (IV) oxide to the atmosphere include Options:
  A) respiration, decay and combustion
  B) photosynthesis, respiration and transpiration
  C) ozone depletion, combustion and decay
  D) photosynthesis, decay and respiration
  Show Answer
  The correct answer is A .
• Question 112:

  CuO_(s) + H_2(g) ↔ Cu_(s) + H₂O_(l)

  What is the effect of increasing the pressure on the equilibrium reaction above?

  Options:
  A) The equilibrium is shifted to the left
  B) The equilibrium is shifted to the right
  C) There is no effect
  D) More H_2(g) is produced
  Show Answer
  The correct answer is C .
• Question 113:

  

  The compound above contains

  Options:
  A) Sp ³ hybridized carbon atoms only
  B) Sp ² hybridized carbon atoms only
  C) Sp ³ and Sp hybirdized carbon atoms
  D) Sp ³ and Sp ²
  Show Answer
  The correct answer is D .
• Question 114:

  When an acidic solution is diluted, what happens to its pH?

  Options:
  A) It depends on the specific acid
  B) It decreases
  C) It remains the same
  D) It increases
  Show Answer
  The correct answer is D .
• Question 115:

  Which of the following statements about catalyst is false?

  Options:
  A) biological catalysts are called enzymes
  B) catalyst do not appear in the balanced equation
  C) catalyst reduce the activation energy for a reaction
  D) catalysts do not alter the mechanism of the reaction and never appear in the rate low
  Show Answer
  The correct answer is D .
• Question 116:

  Which of these sources of water may likely contain the least concentration of Ca${}^{2+}$ and Mg${}^{2+}$?

  Options:
  A) Spring water
  B) River water
  C) Tap water
  D) Sea water
  Show Answer
  The correct answer is C .
• Question 117:

  How many electrons will be found in the nucleus of an atom with mass number 23 and 17 neutrons?

  Options:
  A) none
  B) 6
  C) 7
  D) 8
  Show Answer
  The correct answer is A .
• Question 118: Nigerian crude oil is described as light crude because of its Options:
  A) low sulphur content
  B) high natural gas content
  C) high octane number
  D) low aliphatic-hydrocarbon content
  Show Answer
  The correct answer is A .
• Question 119:

  The presence of ammonia gas in a desiccator can exclusively be removed by

  Options:
  A) phosphorus (V) oxide
  B) fused calcium chloride
  C) calcium chloride
  D) concentrated tetraoxosulphate (VI) acid
  Show Answer
  The correct answer is D .
• Question 120:

  The velocity, V of a gas is related to its mass, M by (k = proportionality constant)

  Options:
  A) V = $\frac{k}{M}$
  B) V = $\frac{k}{M^{\frac{1}{2}}}$
  C) V = $k{M}^2$
  D) V = $(\frac{k}{M}{)}^{\frac{1}{2}}$
  Show Answer
  The correct answer is B .