a,
Gọi a, b là mol Zn, ZnO.
$\Rightarrow 65a+81b=20,8$ (1)
$2CH_3COOH+Zn\to (CH_3COO)_2Zn+ H_2$
$2CH_3COOH+ZnO\to (CH_3COO)_2Zn+ H_2O$
$\Rightarrow 22,4a=2,24$ (2)
(1)(2)$\Rightarrow a=0,1; b=0,177$
$\%m_{Zn}=\frac{0,1.65.100}{20,8}=31,25\%$
$\%m_{ZnO}=68,75\%$
b,
$n_{CH_3COOH}= 2a+2b=0,554mol$
$\Rightarrow m_{dd CH_3COOH}=0,554.60:20\%=166,2g$