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: Consider the following exothermic reaction 2SO₂(g) + O₂(g) = 2SO₃ (g) . If the temperature of the reaction is reduced from 800_oC to 500_oC, and no other change takes place, then Options:
  A) the reaction rate increases
  B) concentration of SO₃ decreases
  C) concentration of SO₃ increases
  D) SO₂ gas becomes unreactive
  E) O₂ gas becomes unreactive
  Show Answer
  The correct answer is C .
• Question 142:

  

  Use the table above to answer this question. The element that is likely to participate in covalent rather than ionic bonding is

  Options:
  A) Z
  B) Y
  C) X
  D) W
  Show Answer
  The correct answer is C .
• Question 143: Geometric isomerism can exist in Options:
  A) hex-3-ene
  B) hexane
  C) prop-l-ene
  D) 3-methyl but -l-ene
  Show Answer
  The correct answer is A .
• Question 144:

  

  The gas that is removed by the water in the flask is

  Options:
  A) O₂
  B) SO₂
  C) HCI.
  D) H₂
  Show Answer
  The correct answer is C .
• Question 145:

  An organic functional group which can likely decolorize ammoniacal silver nitrate is?

  Options:
  A) alkene
  B) alkane
  C) alkyne
  D) alkanol
  Show Answer
  The correct answer is C .
• Question 146: The exhaust fumes from a garage in a place that uses petrol of high sulphur content are bound to contain? Options:
  A) CO and SO₃
  B) CO and SO₂
  C) CO,SO₂ and SO₃
  D) CO and H₂S
  Show Answer
  The correct answer is B .
• Question 147: A fixed mass of gas a volume of 92cm³ at 3°C. When will be its volume at 18C if the pressure remains constant? Options:
  A) 15.3cm³
  B) 87.3cm³
  C) 2.0cm³
  D) 97.0cm³
  Show Answer
  The correct answer is D .
• Question 148: Which of the following statements is correct about the periodic table? Options:
  A) Elements in the same group have the same number of electron shells
  B) The non-metallic properties of the elements tend to decrease across each period
  C) Elements in the same period have the same number of valence electrons
  D) The valence electrons of the elements increase progressively across the period
  Show Answer
  The correct answer is D .
• Question 149: ${}_{88}^{226}Ra$ → ${}_{86}^{x}Rn$ + alpha particle Options:
  A) 226
  B) 220
  C) 227
  D) 222
  Show Answer
  The correct answer is D .
• Question 150:

  Which of the following will give a precipitate with an aqueous solution of copper (I) chloride?

  Options:
  A) But-2-ene
  B) But-1-ene
  C) But-2-yne
  D) But-1-yne
  Show Answer
  The correct answer is D .