4)
a) \(C+O_2\underrightarrow{t^o}CO_2\)
b) \(4P+5O_2\underrightarrow{t^o}2P_2O_5\)
c) \(3Fe+2O_2\underrightarrow{t^o}Fe_3O_4\)
d) \(CH_4+2O_2\underrightarrow{t^o}CO_2+2H_2O\)
5)
a) \(n_{Zn}=\dfrac{6,5}{65}=0,1\left(mol\right)\); \(n_{O_2}=\dfrac{3,2}{32}=0,1\left(mol\right)\)
PTHH: 2Zn + O2 --to--> 2ZnO
Xét tỉ lệ \(\dfrac{0,1}{2}< \dfrac{0,1}{1}\) => Zn hết, O2 dư
PTHH: 2Zn + O2 --to--> 2ZnO
0,1-->0,05------>0,1
=> \(m_{O_2\left(dư\right)}=\left(0,1-0,05\right).32=1,6\left(g\right)\)
b) \(m_{ZnO}=0,1.81=8,1\left(g\right)\)