Gọi CTHH là CuxOy
Ta có: \(\%Cu=\frac{64x}{80}\times100\%=80\%\)
\(\Leftrightarrow\frac{64x}{80}=0,8\)
\(\Rightarrow64x=64\)
\(\Leftrightarrow x=1\)
Ta có: \(PTK_{CuO_y}=80\)
\(\Leftrightarrow NTK_{Cu}+yNTK_O=80\)
\(\Leftrightarrow64+16y=80\)
\(\Leftrightarrow y=\frac{80-64}{16}=1\)
Vậy CTHH là CuO