[Nfb-science] Helping To Balance Chemical Equations

[Tuan Nguyen]

Hi everyone, 
Can someone please help me with the following balancing chemical equations: 
1. methane(CH4) plus sulfate ion(SO4(2minus)) yields hydrogen sulfide(H2S) plus carbon dioxide(CO2)
The next four equations concerned with balancing oxidation-reduction reactions:
2. the reduction of arsenate AsO4(3minus) to arsenite (AsO3(3minus) coupled with the oxidation of hydrogen gas H2 to water H2O
3. the oxidation of Zn metal to Zn(2plus) coupled with the reduction of O2 to water H2O
4. the oxidation of lead sulfide PbS to lead sulfate PbSO4 coupled with the reduction Fe(3plus) to Fe(2plus)
5. the oxidation of lead sulfide to lead sulfate coupled with the reduction of O2 to water H2O
Thanks so much in advanced for the help,
Tuan