Balance redox reaction.
Fe(s) + O2(g) + H2O(l)-->Fe2+(aq) +OH-
O goes frm zero to -2
Fe goes from zero to +2
but on the left, one has O2, so we need two Fe
2Fe(s)+O2+H2O >>>> 2Fe+2 + OH-
that balances charge, but mass has to be balanced...
2Fe + O2 + 2H2O>>>>2Fe+2(aq) + 4OH-
check that.
To balance a redox reaction, you need to ensure that the number of atoms and charges on both sides of the reaction equation are equal. Here's how you can balance the given redox reaction equation:
Step 1: Write down the skeleton equation:
Fe(s) + O2(g) + H2O(l) → Fe2+(aq) + OH-
Step 2: Identify the atoms undergoing oxidation and reduction:
In this reaction, Fe is being oxidized from 0 to +2, and O is being reduced from 0 to -2.
Step 3: Start by balancing the atoms that are not part of redox reactions:
Fe(s) + O2(g) + H2O(l) → Fe2+(aq) + OH-
Balancing Fe: Insert a coefficient of 2 in front of Fe2+(aq):
Fe(s) + O2(g) + H2O(l) → 2Fe2+(aq) + OH-
Step 4: Balance oxygen atoms:
On the left side, there are two oxygen atoms in O2 and one in H2O. To balance, add a coefficient of 2 in front of H2O:
Fe(s) + O2(g) + 2H2O(l) → 2Fe2+(aq) + OH-
Now there are four oxygen atoms on each side.
Step 5: Balance hydrogen atoms:
On the left side, there are 4 hydrogen atoms in H2O. To balance, add a coefficient of 4 in front of OH-:
Fe(s) + O2(g) + 2H2O(l) → 2Fe2+(aq) + 4OH-
Now, there are 8 hydrogen atoms on each side.
Step 6: Balance charges:
On the left side, the total charge is 0. On the right side, each Fe2+ ion carries a charge of +2, and each OH- ion carries a charge of -1. To balance the total charge, add a coefficient of 4 in front of OH-:
Fe(s) + O2(g) + 2H2O(l) → 2Fe2+(aq) + 4OH-
Now, the total charge on both sides is balanced.
The balanced equation for the redox reaction is:
Fe(s) + O2(g) + 2H2O(l) → 2Fe2+(aq) + 4OH-