Chemistry Balancing Redox Reactions

In summary, the conversation discusses balancing the equation H_{2} + O_{2} \rightarrow H_{2}O as a redox reaction. The oxidation numbers of hydrogen and oxygen in the molecule H_{2}O are -2 and +1, respectively, which cancel out to give the molecule a charge of 0. The video mentioned also discusses balancing the equation in terms of moles.
  • #1
frozonecom
63
0

Homework Statement



[tex]H_{2} + O_{2} \rightarrow H_{2}O[/tex]

Homework Equations





The Attempt at a Solution


Well, my classmates insist that H= +1 and O= -2 (in the products side)
so, my Hydrogen will be my Reducing agent because it underwent Oxidation and my Oxygen will be my Oxidizing agent because it underwent Reduction

Reduction: [tex]O_{2} \rightarrow H_{2}O[/tex]
Oxidation: [tex]H_{2} \rightarrow H_{2}O[/tex]

From here on, I can't understand anything.

Well, I need to know what to do here. I was told by this video:

https://www.youtube.com/watch?v=AyKiYz-YpSw

Particularly in 4:09, in that problem, she said that [tex]H_{2}O[/tex] has a charge of 0. I know that Hydrogen and Oxygen in the reactants side has 0 charge / oxidation number too because it is in its "pure" form. So, is this equation "BALANCE-able" ??
 
Last edited by a moderator:
Physics news on Phys.org
  • #2
Molecule of H2O is neutral (has a charge of 0), but oxidation numbers of oxygen and hydrogen in the molecule are -2 and +1 respectively. They just cancel out in the molecule.
 
  • #3
Borek said:
Molecule of H2O is neutral (has a charge of 0), but oxidation numbers of oxygen and hydrogen in the molecule are -2 and +1 respectively. They just cancel out in the molecule.

ooh. Now I get it. Sorry for the dumb question. She just did it faster and not saying that the charges cancel each other. Thanks. :)
But, what is the overall reaction? The balanced one with the electrons and such. I can't understand it.
 
  • #4
I don't like the video, it is slightly chaotic.

While H2/O2 is a redox reaction, trying to balance it as a redox is a waste of time. Are you asked to balance it as redox, or just to balance? Final effect will be exactly the same.
 
  • #5
Borek said:
I don't like the video, it is slightly chaotic.

While H2/O2 is a redox reaction, trying to balance it as a redox is a waste of time. Are you asked to balance it as redox, or just to balance? Final effect will be exactly the same.

Yeah, we are asked to balance it (as in moles)
then as redox. Sorry for the late reply.
 

1. What is a redox reaction?

A redox reaction, short for reduction-oxidation reaction, is a type of chemical reaction in which there is a transfer of electrons between two or more substances. One substance loses electrons (oxidation) while another gains electrons (reduction).

2. Why is balancing redox reactions important?

Balancing redox reactions is important because it allows us to accurately determine the amount of each substance involved in the reaction. This is crucial in understanding the stoichiometry, or the quantitative relationship between reactants and products, of the reaction.

3. How do you balance a redox reaction?

To balance a redox reaction, you need to follow these steps:
1. Identify the substance being oxidized and the substance being reduced.
2. Write the half-reactions for both oxidation and reduction.
3. Balance the atoms in each half-reaction, excluding oxygen and hydrogen.
4. Balance the oxygen atoms by adding water molecules to the side that is lacking oxygen.
5. Balance the hydrogen atoms by adding H+ ions to the side that is lacking hydrogen.
6. Balance the charges by adding electrons to the side that is more positively charged.
7. Make sure the number of electrons in each half-reaction is equal.
8. Combine the two half-reactions to form the overall balanced redox reaction.

4. What is the purpose of using the half-reaction method to balance redox reactions?

The half-reaction method is a systematic approach to balancing redox reactions that allows us to clearly see the changes in oxidation numbers and the transfer of electrons. It also allows us to balance the reaction in an acidic or basic solution by using different methods for balancing the hydrogen and oxygen atoms.

5. Can you provide an example of balancing a redox reaction using the half-reaction method?

Sure, let's look at the reaction between potassium permanganate (KMnO4) and iron(II) sulfate (FeSO4) in an acidic solution:
Step 1: Identify the substances being oxidized and reduced.
KMnO4 is being reduced (gaining electrons), and FeSO4 is being oxidized (losing electrons).
Step 2: Write the half-reactions.
Reduction: MnO4^- + 8H+ + 5e^- → Mn^2+ + 4H2O
Oxidation: Fe^2+ → Fe^3+ + e^-
Step 3: Balance the atoms (excluding oxygen and hydrogen).
Reduction: MnO4^- + 5e^- → Mn^2+
Oxidation: Fe^2+ → Fe^3+ + e^-
Step 4: Balance the oxygen atoms by adding water molecules.
Reduction: MnO4^- + 5e^- → Mn^2+ + 4H2O
Oxidation: Fe^2+ → Fe^3+ + e^- + 2H2O
Step 5: Balance the hydrogen atoms by adding H+ ions.
Reduction: MnO4^- + 5e^- + 8H+ → Mn^2+ + 4H2O
Oxidation: Fe^2+ + 2H+ → Fe^3+ + e^- + 2H2O
Step 6: Balance the charges by adding electrons.
Reduction: MnO4^- + 5e^- + 8H+ → Mn^2+ + 4H2O
Oxidation: Fe^2+ + 2e^- + 2H+ → Fe^3+ + e^- + 2H2O
Step 7: Make sure the number of electrons is equal in both half-reactions.
Reduction: MnO4^- + 5e^- + 8H+ → Mn^2+ + 4H2O
Ox

Similar threads

Stoichiometry of reaction
    • Biology and Chemistry Homework Help
Replies
5
Views
1K
How to get the balanced redox equation in this sample problem?
    • Biology and Chemistry Homework Help
Replies
8
Views
2K
Can Methane and Citric Acid be Balanced in a Redox Reaction?
    • Biology and Chemistry Homework Help
Replies
3
Views
2K
Balance Redox Reaction: 2PbO2 + 4H+ = 2Pb 2+ + O2 + 2H2O
    • Biology and Chemistry Homework Help
Replies
1
Views
2K
Determine if reactions are redox
    • Biology and Chemistry Homework Help
Replies
2
Views
1K
Is 3FeCl2 to 2FeCl3 and Fe(s) a Disproportionation Redox Reaction?
    • Biology and Chemistry Homework Help
Replies
1
Views
3K
What will be the product of this organic reaction?
    • Biology and Chemistry Homework Help
Replies
28
Views
4K
Redox reaction-naming the substance reduced
    • Biology and Chemistry Homework Help
Replies
4
Views
2K
Chemistry Balancing Redox Reaction: FeS2+Na2O2→Na2FeO4+Na2SO4+Na2O"
    • Biology and Chemistry Homework Help
Replies
3
Views
2K
Combustion Reactions: C5H12 + O2 - Steps & Oxidation States
    • Biology and Chemistry Homework Help
Replies
6
Views
2K

Hot Threads

Recent Insights

Back
Top