nAl= 6,75/27=0,25(mol)
nZn= 9,75/65= 0,15(mol)
4 Al + 3 O2 -to-> 2 Al2O3
0,25____0,1875___0,125(mol)
Zn + 1/2 O2 -to->ZnO
0,15___0,075___0,15(mol)
=> n(O2, tổng)= 0,1875+ 0,075= 0,2625(mol)
PTHH: 2 KMnO4 -to-> K2MnO4 + MnO2 + O2
0,525<----------------------------------------------0,2625(mol)
=> mKMnO4= 0,525.158= 82,95(g)
=> m=82,95(g)
Giải chi tiết cho mik nhé!