Balance las ecuaciones por el método de oxido reducción recuerde Indicar Oxidante, reductor, agente oxidante, agente reductor

1. HI + H2SO4 → SO2 + I2 + H2O

2. SO2 + O2 + CaCO3 → CaSO4 + CO2

3. PbS + Cu2S + HNO3 → Pb(NO3)2 + Cu(NO3)2 + NO2 + S + H2O

4. H2O2 + KMnO4 + H2SO4 → K2SO4 + MnSO4 + O2 + H2O

whoa this is hard i really dont know

answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

that's it!

if you need further assistance, let me know: )

~ trueboss72