I need a balanced chemical equation for the titration of potassium iodate (KIO3^2-) and sodium thiosulfate (Na2S2O3^2-).
This is what I have, but I was wondering if I should cancel the spectator ions:
Na2S2O3 (aq) + 2KIO3 (aq) --> K2S2O3 (aq) + 2NaIO3(aq)
Surely you are confused a little or I just don't know what's going on. Usually something like KI is added to the KIO3 and that produces I2, then the I2 is titrated with Na2S2O3. To my knowledge, thiosulfate used as a titrant is used only for I2.
To write a balanced chemical equation, we need to ensure that the number of individual atoms of each element is the same on both sides of the equation. In this case, the equation you have written is almost correct, but you should cancel the spectator ions.
The balanced chemical equation for the titration of potassium iodate (KIO3^2-) and sodium thiosulfate (Na2S2O3^2-) is:
2Na2S2O3(aq) + KIO3(aq) --> Na2SO4(aq) + 2NaIO3(aq)
In this equation, the spectator ions are 2Na^+ and 2SO4^2-. Since they are present on both sides of the equation, we can cancel them out to simplify the equation. The revised equation is:
2Na2S2O3(aq) + KIO3(aq) --> 2NaIO3(aq) + Na2SO4(aq)
Note that the coefficients in the balanced equation represent the ratios of moles, not just the numbers of molecules.
To write a balanced chemical equation, we need to make sure that the number of atoms of each element is the same on both sides of the equation.
Let's first write the chemical formulas for the reactants and products:
Reactants:
Sodium thiosulfate: Na2S2O3
Potassium iodate: KIO3
Products:
Potassium thiosulfate: K2S2O3
Sodium iodate: NaIO3
Now, let's balance the equation step by step:
1. Balance the iodine (I) atoms:
Reactants: 2I (from 2KIO3)
Products: 2I (from NaIO3)
So, the equation becomes:
Na2S2O3 (aq) + 2KIO3 (aq) --> K2S2O3 (aq) + NaIO3(aq)
2. Balance the sodium (Na) atoms:
Reactants: 2Na (from Na2S2O3)
Products: 1Na (from NaIO3) and 2Na (from K2S2O3)
So, let's add another Na to the reactants:
2Na2S2O3 (aq) + 2KIO3 (aq) --> K2S2O3 (aq) + NaIO3(aq)
3. Balance the oxygen (O) atoms:
Reactants: 12O (from 2KIO3)
Products: 12O (from 2NaIO3)
The oxygen is already balanced.
4. Finally, balance the sulfur (S) atoms:
Reactants: 2S (from Na2S2O3)
Products: 2S (from K2S2O3)
The sulfur is already balanced.
After balancing all the atoms, the final balanced chemical equation is:
2Na2S2O3 (aq) + 2KIO3 (aq) --> K2S2O3 (aq) + 2NaIO3(aq)
Regarding the spectator ions, they do not participate in the actual reaction and can be canceled out. In this case, the spectator ions are the sodium (Na+) and potassium (K+) ions. So, the simplified balanced equation would be:
S2O3^2- (aq) + IO3^- (aq) --> S2O3^2- (aq) + IO3^- (aq)