How do i combine 2 half ionic equations into an overall equation??
4OHˉ → 2H2O + O2 + 4e
2H+ + 2e → H2
*The "H+" is the hydrogen ion
The correct overall equation is
2H2O → 2H2 + O2
How do i get that???
To combine the two half-ionic equations into an overall equation, you need to cancel out the common ions and balance the equation.
First, let's analyze the two half-ionic equations provided:
Half-Ionic Equation 1: 4OHˉ → 2H2O + O2 + 4e
Half-Ionic Equation 2: 2H+ + 2e → H2
In the first equation, 4 OHˉ ions on the left side combine to form 2 H2O molecules and 1 O2 molecule on the right side, along with the release of 4 electrons (4e).
In the second equation, 2 H+ ions on the left side combine with 2 electrons (2e) to form 1 H2 molecule on the right side.
Now, let's try to make the number of electrons equal in both equations so we can cancel them out. We can achieve this by multiplying each equation by a suitable factor:
Half-Ionic Equation 1: 4OHˉ → 2H2O + O2 + 4e
Half-Ionic Equation 2: 2H+ + 2e → H2 (multiplied by 2)
After multiplying the second equation by 2, we have:
4H+ + 4e → 2H2
Now, the number of electrons is equal in both equations. Next, we can add the two equations together while keeping the left side and the right side separate:
4OHˉ + 4H+ + 4e → 2H2O + O2 + 4e
+
4H+ + 4e → 2H2
Now, we can cancel out the electrons (4e - 4e = 0) and combine the remaining ions and molecules:
4OHˉ + 4H+ + 4H+ → 2H2O + O2 + 2H2
At this point, notice that there are 4 hydrogen ions (H+) on the left side and 4 hydrogen molecules (H2) on the right side. We can simplify this by combining the hydrogen ions and molecules:
4OHˉ + 6H+ → 2H2O + O2
Finally, by dividing every coefficient in the equation by 2 to achieve the simplest ratio, we arrive at the overall balanced equation:
2OHˉ + 3H+ → H2O + 1/2 O2
Keep in mind that 1/2 O2 can be rewritten as O2 when writing the equation in an overall form without fractions.
Therefore, the correct overall balanced equation is:
2H2O → 2H2 + O2