[chucho]

A- ___ KClO3 ---> ___ KCl + ___ O2
B- ___ HCl + ___ Ca(OH)2 ---> ___ CaCl2 + ___ H2O
C- ___ HF + ___ Zn ---> ___ ZnF2 + ___ H2
D- ___ Fe + ___ O2 ---> ___ Fe2O3

[chenbeier]

You have to calculate like 1/2 +1/3 =

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