Post Utme Chemistry Past Questions and Answers

Question 821:

A basic postulate of the kinetic theory of gases is that the molecules of a gas move in straight lines between collisions.
This implies that ____________

A. Collisions are perfectly elastic
B. Forces of repulsion exist
C. Forces of repulsion and attraction are in equilibrium
D. Collisions are inelastic

Question 822:

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

Question 823:

\(X_{(g)} \rightarrow X_{(g)}\) : The type of energy involved in the above transformation is ____________

A. Ionization energy
B. Sublimation energy
C. Lattice energy
D. Electron affinity

Question 824:

Chlorine, consisting of two isotopes of mass number 35 and 37 , has an atomic mass of \(35.5\).
The relative abundance of the isotopes of the isotopes of mass number 37 is ____________

A. 20
B. 25
C. 50
D. 75

Question 825:

\(10.0 dm ^{3}\) of air containing \(H _{2} S\) as an impurity was passed through a solution of \(Pb \left( NO _{3}\right)\) until all the \(H _{2} S\) had reacted. The precipitate of \(PbS\) was found to weigh \(5.02 g\). according to the equation, \(Pb \left( NO _{3}\right)_{2}+ H _{2} S \rightarrow PbS +\) \(2 HNO _{3}\) the percentage by volume of hydrogen sulphide (Pb =207, \& \(4.32 GM 7 .\) at STP \(=22.4 dm ^{3}\) )

A. \(50.2\)
B. \(47.0\)
C. \(4.70\)
D. \(0.47\)