Tham khảo sách 'chemistry part 39, julia burdge,2e (2009)', khoa học tự nhiên, hoá học phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | SUCCESSIVE APPROXIMATION A-5 Using the rule that x can be neglected if the initial acid concentration divided by the Ka is greater than 100 we find that in this case x cannot be neglected X 10 4 21 . Successive approximation involves first neglecting x with respect to initial acid concentration 2 2 -x 10 4 and solving for x x1 X 10 4 X 10 5 x 07 X 10 5 M We then solve for x again this time using the calculated value of x on the bottom of the fraction 2 2 - x - 7 10 10 .r - X 10 4 X 10 6 x X 10 6 M Note that the calculated value of x decreased from to . We now use the new calculated value of x on the bottom of the fraction and solve for x again 2 2 z X 10-4 x - x2 - X 10-4 X 10 6 x x 10 6 M This time the value of x increased slightly. We use the new calculated value and solve for x again. 2 2 X 10-4 -x - 2 - - X IO 4 X 10 6 x X IO 6 M This time we find that the answer is still M so there is no need to repeat the process. In general we apply the method of successive approximation until the value of x obtained does not differ from the value obtained in the previous step. The value of x determined using successive approximation is the same value we would get if we were to use the quadratic equation. Thermodynamic Data at 1 atm and 25 C INORGANIC SUBSTANCES Substance AH kJ mol AG kJ mol S J K mol Ag s 0 0 Ag aq AgCl s AgBr s Agi 5 AgNO3 s Al 5 0 0 Al3 aq AI2O3 s As s 0 0 AsO4- ag AsH3 g H3AsO4 s Au 5 0 0 Au2O3 s AuCl s AuCI3 s B s 0 0 6 5 B2O3 5 H3BO3 s .
