Phương trình chữ:
Aluminium + oxygen \(\rightarrow\) aluminium oxide
Bảo toàn khối lượng:
\(m_{Al}+m_{O_2}=m_{Al_2O_3}\)
\(\Rightarrow m_{Al}=20,4-10,8=9,6g\)
\(PTHH:4Al+3O_2\rightarrow^{t^o}2Al_2O_3\\ \text{Đ}LBTKL:\\ m_{Al}+m_{O_2}=m_{Al_2O_3}\\ \Leftrightarrow10,8+m_{O_2}=20,4\\ \Leftrightarrow m_{O_2}=9,6\left(g\right)\)