Question

? + ? -> MgO 
Zn + HCl -> ? + ? 
CuO + ? -> H2O + ? 
CaO + H2O -> ? 

Answer 1

\(2Mg+O_2\underrightarrow{t^o}2MgO\\ Zn+2HCl\rightarrow ZnCl_2+H_2\\ CuO+H_2\underrightarrow{t^o}Cu+H_2O\\ CaO+H_2O\rightarrow Ca\left(OH\right)_2\)

Answer 2

\(Mg+\dfrac{1}{2}O_2\underrightarrow{t^o}MgO\\ Zn+2HCl\rightarrow ZnCl_2+H_2\\ CuO+H_2\underrightarrow{t^o}Cu+H_2O\\ CaO+H_2O\rightarrow Ca\left(OH\right)_2\)