Potassium has three naturally occurring isotopes. According to one source of data, Potassium-39 (mass 38.9637 AMU) makes up 93.26%, potassium-40 (mass 39.9640 AMU) makes up just 0.01%, and potassium-41 (mass 40.9618 AMU) makes up 6.73%. What is the average atomic mass of potassium based on these relative abundances? Show all your work for credit, and express your final answer to 2 decimal places, and include the unit.

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