Cinnabar is a natural mercury(II) sulfide, HgS, found near volcanic rocks and hot springs. It is the only important source of mercury, which has many uses, including dental amalgams, thermometers, and mercury vapor lamps. Mercury is formed in the following endothermic reaction when mercury(II) sulfide is heated. Consider a system in which a sample of HgS in a closed container is heated with a Bunsen burner flame. 8HgS(s) → 8Hg(l ) + S8(s)
a. Describe the changes in particle motion as heat is transferred from the hot gases of the Bunsen burner flame to the container to the HgS(s).
b. In general terms, explain why energy is absorbed in the reaction. c. Into what form of energy is the heat energy converted for this reaction?

answer : (a) volume of the gas = 8.67 ×   l

                (b) second virial coefficient b = -1.21226 l/mole

solution :   given,     t = 300k

                                p = 20atm

                                z = 0.86

                                n = 8.2 mmoles = 8.2 × moles

                                r =   0.082 l atm/k/mol

        find,     (a) volume of gas   and (b) second virial coefficient b at 300k.

formula used :            

                          and            

(a)            

                    = \times 0.082\times 300}{20}[/tex]

                    = 8.67 ×   l

(b)      

                    = (0.00867-1) × 8.659

                    = - 8.5839 l/mole