KClO₃=clorat de potasiu
1mol KClO₃.......................3*6.023*10²³ atomi oxigen
x moli.................................5.4207*10²³ atomi oxigen
x=5.4207*10²³*1/3*6.023*10²³=0.3moli KClO₃
Masa molara KClO₃=39+35.5+3*16=122.5g/mol
1mol.....................................122.5g KClO₃
0.3moli....................................y
y=0.3*122.5/1=36.75(cantitatea pura)
puritatea=36.75*100/40
puritatea=91.875%