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Chemistry Past Questions and Answers

Jamb 1990 Chemistry Questions

Question 31:
Which of the following terms indicates the number of bonds that can be formed by an atom?
  • A Oxidation number
  • B Valence
  • C Atomic number
  • D Electronegativity
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Question 32:
X(g) → X\(^-\)(g). The type of energy involved in the above transformation is?
  • A Ionization energy
  • B Sublimation energy
  • C Lattice energy
  • D Electron affinity
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Question 33:
Chlorine, consisting of two isotopes of mass numbers 35 and 37, has an atomic mass of 35.5.
The relative abundance of the isotope of mass number 37 is?
  • A 20
  • B 25
  • C 50
  • D 75
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Question 34:
10.0 dm3 of air containing H2S as an impurity was passed through a solution of Pb(NO3)2 until all the H2S had reacted. The precipitate of PbS was found to weigh 5.02 g. According to the equation:
Pb(NO3)2 + H2S → PbS + 2HNO3 the percentage by volume of hydrogen sulphide in the air is?
(Pb = 207, S = 32, GMV at s.t.p = 22.4dm3)
  • A 50.2
  • B 47.0
  • C 4.70
  • D 0.47
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Question 35:
A blue solid, T, which weighed 5.0g was placed on a table. After 8 hours, the resulting pink solid was found to weigh 5.5g. It can be inferred that substance T?
  • A Is deliquescent
  • B Is hydroscopic
  • C Has some molecules of water of crystallization
  • D Is efflorescent
View Answer & Explanation