Kimikal riakshan a pruoses we liid tu di chansfamieshan a wan set a kimikal sobstans tu waneda. Klasikali, kimikal riakshan ingkompas chienj we onggl invalv di pozishan a ilekchran ina di faamin ah brokop a kimikal ban bitwiin atom, wid no chienj tu di nyuukliosdem (no chienj tu di elimentdem we prezant), ah kiah muotaim bi diskraib bai kimikal ikwiejan. Nyuuklier kimischri a wah sob-disiplin a kimischri we invalv di kimikal riakshan a hanstiebl ah riedioaktiv eliment we buot ilekchranik ah nyuuklier chienj maita okor.