apa oxigenata = H2O2
ms = 800 g , c% = 30% , c% = mdx100/ms
=> md = msxc%/100 = 800x30/100 = 240 g apa oxigenata se va descompune
240 g.............................. m g
2H2O2 ----> 2H2O + O2
2x34 ................................ 32
=> m = 240x32/2x34 = aproximativ 113 g O2
n = nr moli = masa / M.moleculara = 113/32 = 3,53 moli O2