a, \(2Cu+O_2\underrightarrow{t^o}2CuO\)
\(2Mg+O_2\underrightarrow{t^o}2MgO\)
b, \(\dfrac{m_{CuO}}{m_{MgO}}=\dfrac{2}{1}\Rightarrow\dfrac{n_{CuO}}{n_{MgO}}=\dfrac{2}{1}:\dfrac{80}{40}=1\)
⇒ nCuO = nMgO (1)
Có: m chất rắn tăng = mO2 = 32 (g)
Theo PT: \(n_{O_2}=\dfrac{1}{2}n_{CuO}+\dfrac{1}{2}n_{MgO}=\dfrac{32}{32}=1\left(mol\right)\left(2\right)\)
Từ (1) và (2) ⇒ nCuO = nMgO = 1 (mol)
⇒ mCuO = 1.80 = 80 (g)
mMgO = 1.40 = 40 (g)