(a)(i) State three differences between electrovalent compound and covalent compound. (ii) Name the type of chemical bonding involved in the formation of ammonium ion from ammonia.
(b)(i) Name the quantum numbers which define an electron within an atom. (ii) State the orbital in which the fifth electron of an atom is most likely to be found. Sketch the shape of the orbital. (iii) State the period and the group to which the element boron belongs in the Periodic Table.
(c)(i) What is meant by the entropy of a chemical system? (ii) Calculate the free energy change for a given reaction at 300 K using the following data obtained for the reaction: \(\Delta\) = -710KJ mol\(^{-1}\); \(\Delta\)S = 0.15 KJ mol\(^{-1}\)K\(^{-1}\) (iii) From your evaluation in (c)(i) above, state whether the reaction is spontaneous or not at the given temperature. Give reason for your answer.
Explanation
(a)(i)
Electrovalent compounds
Convalent convounds
The compound is made up of an aggregate of ions of opposite charges.Can conduct electricity as electrolyte.Can dissolve in water.
Made up of moleculesCannot conduct electricityCan only dissolve in organic solvents such as ether.
(ii) Coordinate or the active bond.
(b)(i) The principal quantum number, angular momentum quantum number, Magnetic Orbital quantum number and magnetic spin quantum number. (ii) The 2 p-orbital group 3A and period two
(c)(i) The measure of the degree of disorderliness or randomness of a chemical system. (ii) \(\Delta\) G = \(\Delta\) H - T\(\Delta\) S = -710 - 300(0.15) = -710 - 45 = -755 KJ/mol (iii) The reaction is spontaneou because \(\Delta\) G is negative.
