Chemistry

posted by .

Having trouble balancing redox equations. Teacher says I should use the method of half reactions and I'm not sure how. Any explanation or formula would be nice.

C6H12O2 --> C2H4O2

SO2+H2O+O2 --> H2SO4

C2H6O+O2 --> CO2 + H2O

  • Chemistry -

    I disagree that the half reaction method is easier in all circumstances; in fact, I think it is harder to do them this way for these three than straight trial and error. Let me illustrate on the last one. Here is what I do.
    C2H6O + O2 ==> CO2 + H2O
    I look and see 2C on the left so let's make it 2 on the right.
    C2H6O + O2 ==> 2CO2 + H2O

    That takes care of C. Now let's do H. I have 6 on the left, let's get 6 on the right.
    C2H6O + O2 ==> 2CO2 +3H2O

    We now know (or highly suspect, that the coefficients on the right are now "in stone". So let's count up O on the right and make that balance on the left. We have 3 + 4 = 7 O on the right. On the left we have 1 from C2H6O which leave 6 unaccounted for. So we add 3 for the O2.
    C2H6O + 3O2 ==> 2CO2 + 3H2O

    With a little practice these can be done in minimal time.
    Let's do the second one this way and see if it's just as easy.
    SO2+H2O+O2 --> H2SO4

    I see 1 S on the left and 1 on the right along with 2 H on the left and 2 on the right so my first inclination is to leave that SO2 and H2O on the left and H2SO4 on the right alone. Let's count up O and see where we are. We have 4 O on the right and 3 from the SO2 + H2O (notice I don't count the O2 because that's the only one I can change). So we need one more O on the left. I can get that bv 1/2 O2 (1/2 * 2 = 1) so let's put that in.
    SO2 + H2O + 1/2 O2 --> H2SO4
    But of course we can't use fractions. How do we get rid of the 1/2. Just multiply everything by 2 which gives us
    2SO2 + 2H2O + O2 ==> 2H2SO4.
    Voila!

    Is something missing from #1?

  • Chemistry -

    yes I apologize,
    #1 is C6H12O6 --> C2H4O2

    thankyou for all your help!

  • Chemistry -

    C6H12O6 ==> 3C2H4O2

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. General Chemistry

    Im having trouble balancing this redox rection in acidic solution. I don't know how to balance reactions in which one reactant splits up into two products. C2H5OH(aq) + I3-(aq) --> I-(aq) + CO2(g) + CHO2-(aq) + H+(aq) I know I split …
  2. chemistry- redox

    Complete and balance the following equations using the method of half-reaction. both reactions happen in acidic solutions: a. Cu(s) + NO3-(aq)--> Cu2+(aq) + NO2(aq) b. Mn2+(aQ) + NaBiO3(s)--> Bi3+(aq) + MnO4-(aq) I'm having trouble …
  3. chemistry II

    What are the steps to balancing Redox reactions using the Valence method. thanks> ex problem: NH3+O2 -->H2O +NO
  4. Chemistry Honors

    I need help balancing equations 1) CH4+O2-->CO2-->+H2O 2) Hf+N2-->Hf3N4 3) Mg+H2SO4-->MgSO4+H2 4) C2H6+O2 -->CO2+H2O 5) Pb(NO3)2 + NaI--> PbI2+NaNO3 6) Fe+O2-->Fe3O4
  5. Chemistry

    Please help me verify: The following reactions are involved in the formation of acid rain. Use oxidation numbers to identify which of these reactions are REDOX reactions. a. 2SO2(g) + O2(g) �� 2SO2(g) -2 -2 0 -2 -2 No …
  6. Chemistry

    Use oxidation numbers to identify if this reaction is REDOX reactions. SO2(g) + H2O(l) -> H2SO3(aq) for oxidation #s I got: SO2 = -2 for the S = -2 for the o2 H20 = +1 for H2 = -2 for O --> H2SO = +1 for H2 = -2 for S = -2 for …
  7. chemistry

    I am having trouble balancing one of the half reactions: AsO3^(-3) --> AsO4^(-4) Which side should OH and H2O go?
  8. chemistry-balanced redox equations

    Use the following steps to balance the redox reaction below: Mg + Au+ Mg2+ + Au a. Write the oxidation and reduction half-reactions. Make sure each half-reaction is balanced for number of atoms and charge b. Multiply each half-reaction …
  9. Chemistry- balancing Redox

    Can anyone please assist showing half reactions balancing, balancing of e- and the additions of H2O, H+ and then since its BASIC!!!! the final addition of OHs?
  10. Chemistry

    Dr.Bobb222 please help balance the following oxidation-reduction reactions, which occur in acidic solution, using the half-reaction method. (Use the lowest possible coefficients. Include states-of-matter under the given conditions …

More Similar Questions