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Saturday, 23 May 2026
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Chemistry Past Questions and Answers

Jamb 1997 Chemistry Questions

Question 6:
The temperature of a body decreases when drops of liquid placed on it evaporate because?
  • A The atmospheric vapour pressure has a cooling effect on the body
  • B A temperature gradient exists between the drops of liquid and the body causing the latter to vaporate
  • C The heat of vapourization is drawn from the body causing it to cool
  • D The random motion of the liquid molecules causes a cooling effect on the body
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Question 7:
The electron configuration of two elements with similar chemical properties are represented by?
  • A 1s<sup style='font-size: smaller;'>2</sup>2s<sup style='font-size: smaller;'>2</sup>2p<sup style='font-size: smaller;'>5</sup> and 1s<sup style='font-size: smaller;'>2</sup>2s<sup style='font-size: smaller;'>2</sup>2p<sup style='font-size: smaller;'>4</sup>
  • B 1s<sup style='font-size: smaller;'>2</sup>2s<sup style='font-size: smaller;'>2</sup>2p<sup style='font-size: smaller;'>4</sup> and 1s<sup style='font-size: smaller;'>2</sup>2s<sup style='font-size: smaller;'>2</sup>2p<sup style='font-size: smaller;'>6</sup>3s<sup style='font-size: smaller;'>1</sup>
  • C 1s<sup style='font-size: smaller;'>2</sup>2s<sup style='font-size: smaller;'>2</sup>2p<sup style='font-size: smaller;'>6</sup>3s<sup style='font-size: smaller;'>1</sup> and 1s<sup style='font-size: smaller;'>2</sup>2s<sup style='font-size: smaller;'>1</sup>
  • D 1s<sup style='font-size: smaller;'>2</sup>2s<sup style='font-size: smaller;'>2</sup>2p<sup style='font-size: smaller;'>4</sup> and 1s<sup style='font-size: smaller;'>2</sup>2s<sup style='font-size: smaller;'>1</sup>
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Question 8:
In the periodic table, what is the property that decreases along the periodic and increases down the group?
  • A Atomic number
  • B Electron affinity
  • C Ionization potential
  • D Atomic radius
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Question 9:
Two elements, P and Q with atomic numbers 11 and 8 respectively , combine chemically to form the compound PxQY. The respective values of x and y are?
  • A 1 and 1
  • B 1 and 2
  • C 2 and 1
  • D 3 and 1
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Question 10:
Oxygen is a mixture of two isotopes 16-O and 18-O with relative abundances of 90% and 10% respectively. The relative atomic mass of oxygen is?
  • A 16.0
  • B 16.2
  • C 17.0
  • D 18.0
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