Câu 3:
a, Ta có: \(n_{O_2}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\)
b, Ta có: 0,98 kg = 980 (g)
\(\Rightarrow n_{H_2SO_4}=\dfrac{980}{98}=10\left(mol\right)\)
c, Ta có: \(n_{O_2}=\dfrac{12.10^{22}}{6.10^{23}}=0,2\left(mol\right)\)
Câu 4:
Giả sử: \(\left\{{}\begin{matrix}n_{N_2}=x\left(mol\right)\\n_{O_2}=y\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow\dfrac{x}{y}=\dfrac{2}{1}\Leftrightarrow x-2y=0\left(1\right)\)
Mà: mA = 8,8 (g)
\(\Rightarrow28x+32y=8,8\left(2\right)\)
Từ (1) và (2) \(\Rightarrow\left\{{}\begin{matrix}x=0,2\left(mol\right)\\y=0,1\left(mol\right)\end{matrix}\right.\)
Bạn tham khảo nhé!