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Câu 30)

$\rightarrow$ $\text{B) 7,3g}$

$\text{Zn+2HCl$\rightarrow$ZnCl2+H2}$

Áp dụng định luật bảo toàn khối lượng:

$\text{mHCl=mZnCl2+mH2-mZn}$

$\rightarrow$ $\text{mHCl=13,6+0,2-6,5=7,3g}$

Câu 31)

$\rightarrow$ $\text{D) 2,6g}$

$\text{CH4+2O2$\xrightarrow{t^o}$CO2+2H2O}$

Áp dụng định luật bảo toàn khối lượng:

$\text{mCH4+mO2=mCO2+mH2O}$

$\rightarrow$ $\text{mCH4=1,4+1,6-0,4=2,6g}$

Câu 32)

$\text{1) 2Zn+O2$\xrightarrow{t^o}$2ZnO}$

$\text{2) 2KClO3$\xrightarrow{t^o}$2KCl+3O2}$

$\text{3) Mgo+H2SO4$\rightarrow$MgSO4+H2}$

$\text{4) CaO+2HCl$\rightarrow$CaCl2+H2O}$

$\text{5) CH4+2O2$\xrightarrow{t^o}$CO2+2H2O}$

$\text{6) 2Al(OH)3$\xrightarrow{t^o}$Al2O3+3H2O}$

$\text{7) NaCl+AgNO3$\rightarrow$NaNO3+AgCl}$

$\text{8) K2SO3+H2SO4$\rightarrow$K2SO4+H2O+SO2}$

$\text{9) 2Fe+3Cl2$\xrightarrow{t^o}$2FeCl3}$

$\text{10) Fe3O4+4H2$\xrightarrow{t^o}$3Fe+4H2O}$

Câu 33)

$\text{Zn+2HCl$\rightarrow$ZnCl2+H2}$

Tỉ lệ: $\text{1:2:1:1}$