Writing half reactions
Moderators: Chem_Mod, Chem_Admin
-
- Posts: 106
- Joined: Fri Sep 28, 2018 12:28 am
Writing half reactions
When given a question like the one attached, where the given reactions have H+ like part c, how do I know on which equation to write the H+ on when doing the half reactions?
-
- Posts: 66
- Joined: Fri Sep 28, 2018 12:16 am
Re: Writing half reactions
The H+ will be with the Cr207 because the h20 will be included with this half reaction to balance the oxygens, and the H+ will be needed the balance the hydrogens from the h20.
-
- Posts: 61
- Joined: Fri Sep 28, 2018 12:23 am
Re: Writing half reactions
When a molecule consists of an oxygen atom/s and changes (becomes product / or is reversed into reactant) into its elemental form (i.e. MnO4- becomes Mn2+), you must accommodate for the missing oxygen atom/s. Therefore, when the reaction occurs in an acidic solution, you add H2O to the side without the oxygen and add H+ to the side with the oxygen (to balance the new H atoms from the addition of water). So for this question, you keep the H+ ions with the Cr2O7(2-) because that will be the reaction that requires additional O atoms to balance it.
-
- Posts: 58
- Joined: Fri Sep 28, 2018 12:16 am
Re: Writing half reactions
The H+ would be with the Cr2O7 since the oxygen atoms in it are balanced with H20, and the H20 are balanced with H+
-
- Posts: 69
- Joined: Fri Sep 28, 2018 12:23 am
Re: Writing half reactions
It will end up depending on which half reaction requires the H+. You need to balance both half reactions and know that you should end up with (in that example) 8H+ on the left side of the equation.
-
- Posts: 60
- Joined: Fri Sep 28, 2018 12:24 am
Re: Writing half reactions
The H+ would be with the Cr2O7 since the oxygen atoms in it are balanced with H20, and the H20 are balanced with H+
-
- Posts: 37
- Joined: Fri Sep 28, 2018 12:22 am
Re: Writing half reactions
You would put the H+ with the Cr2O7 since the oxygen atoms are balanced with H20, and the H20 is balanced with the H+
-
- Posts: 46
- Joined: Fri Sep 28, 2018 12:16 am
Re: Writing half reactions
since oxygen atoms are balanced with H20, you have to then balance the H20 with H+. Because of this, you would put the H+ with the Cr2O7
Return to “Balancing Redox Reactions”
Who is online
Users browsing this forum: No registered users and 11 guests