8=верно только а
9=в
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Zn+H2SO4=ZnSO4+H2
n(Zn)=n(H2)
n(Zn)=m/M
n(Zn)=13/65=0.2 (моль)
V(H2)=n*Vm
V(H2)=0.2*22.4=4.48 (л)
Na2SO4 = 142 г/моль
w(Na) = 23*2/142 = 0,3239 = 32,39%
w(S) = 32/142 = 0,225 = 22,5%
w(O) = 16*4/142 = 0,45 = 45%