4. 2H2O2=2H2O+O2

5. 2HgO=2Hg+O2

6. SO2 Mr(SO2)= 64

w(S)= 32/64=0,5=50%

w(O)=32*2/64=0.5=50%

KClO3 Mr(KClO3)=122,5

W(K)=39/122,5=0.32=32%

w(Cl)= 35,5/122,5=0.29=29%

w(O)= 3*16/122,5= 0.39=39%