What are the steps to balancing Redox reactions using the Valence method. thanks> ex problem:

NH3+O2 -->H2O +NO

To balance a redox reaction using the Valence method, follow these steps:

Step 1: Assign oxidation numbers
Determine the oxidation numbers for each element in the reactants and the products. In this case, we have NH3, O2, H2O, and NO. The oxidation number of hydrogen is +1, oxygen is -2, and nitrogen is -3 in NH3. Oxygen is 0 in O2. The oxidation number of hydrogen is +1 and oxygen is -2 in H2O. The oxidation number of nitrogen is +2 in NO.

Step 2: Identify the oxidized and reduced elements
Determine which elements are being oxidized and reduced. The element that increases in oxidation number is being oxidized, while the element that decreases in oxidation number is being reduced. In this case, nitrogen is being oxidized from -3 to +2, so it is the oxidized element. Oxygen is being reduced from 0 to -2, so it is the reduced element.

Step 3: Write the balanced half-reactions
Now, separate the reaction into two half-reactions, one for the oxidation and one for the reduction.

Oxidation half-reaction:
NH3 → NO

Reduction half-reaction:
O2 → H2O

Step 4: Balance the atoms and charges in each half-reaction
First, balance the atoms in each half-reaction, excluding hydrogen and oxygen. In the oxidation half-reaction, we have one nitrogen on the left and one on the right, so it is already balanced. In the reduction half-reaction, we have two oxygens on the left and two on the right, so it is also balanced.

Next, balance the charges in each half-reaction. In the oxidation half-reaction, we have a charge of -3 on the left and no charge on the right. To balance the charges, we need to add 3 electrons (e-) to the right side.

NH3 → NO + 3e-

In the reduction half-reaction, we have no charge on the left and a charge of -2 on the right. To balance the charges, we need to add 2 electrons (e-) to the left side.

2e- + O2 → H2O

Step 5: Combine the half-reactions
Multiply each half-reaction by the appropriate factor so that the number of electrons lost in the oxidation half-reaction equals the number of electrons gained in the reduction half-reaction.

2NH3 → 2NO + 6e-
4e- + O2 → 2H2O

Step 6: Balance the remaining atoms
Finally, balance the remaining atoms, including hydrogen and oxygen, in the overall reaction.

To balance the nitrogen atoms, multiply the oxidation half-reaction by 2, and balance the hydrogen atoms by adding 3 H2O to the reduction half-reaction.

4NH3 → 4NO + 12e-
4e- + O2 → 2H2O + 2H2O

Now, combine the two half-reactions into the balanced overall reaction:

4NH3 + 4e- + O2 → 4NO + 2H2O

This is the balanced redox reaction using the Valence method.