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Topic: going in circles when balancing equation  (Read 38386 times)

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KD00LS

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Re: going in circles when balancing equation
« Reply #15 on: April 15, 2006, 01:27:53 PM »
I'll have to snoop around in those files. I'm new to the site so I haven't really explored.
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Offline Borek

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Re: going in circles when balancing equation
« Reply #16 on: April 21, 2006, 06:58:26 AM »
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Offline Mitch

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Re: going in circles when balancing equation
« Reply #17 on: April 21, 2006, 03:55:16 PM »
Page error: http://www.chembuddy.com/?left=balancing-stoichiometry&right=balancing-inspection

XML Parsing Error: mismatched tag. Expected: </p>. Location: http://www.chembuddy.com/?left=balancing-stoichiometry&right=balancing-inspection Line Number 110, Column 5: </div> ----^
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Offline Mitch

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Re: going in circles when balancing equation
« Reply #18 on: April 21, 2006, 03:56:47 PM »
(2)P4O6 -> (1/2)P4 + (3)P2O4

That was a really easy one by inspection. :)
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Offline Mitch

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Re: going in circles when balancing equation
« Reply #19 on: April 21, 2006, 04:14:48 PM »
(5/16)P2I4 + (13/32)P4 + (4)H2O -> (5/4)PH4I + (1)H3PO4

The above is also a very easy one for me to do by inspection. Most people will not want to use fractions and will get caught up avoiding them. But if you just run with them and are comfortable enough with them its no big thing. And, then at the end you can multiply by 32 and get a more aesthetically pleasing form.
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Offline Borek

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Re: going in circles when balancing equation
« Reply #20 on: April 21, 2006, 04:55:20 PM »
Thanks for that </p> tag. For some reason Opera behaves differently than before - instead of stopping of the first error it goes into quirks mode and renders everything, displaying error messages below, that's why I am missing these things now :( Have to check what's going on, perhaps something is wrong with the headers sent (XHTML/HTML)?

As for the equations - I am not stating they are impossible, but they ARE harder than most other examples. But I am open to suggestions - just bear in mind that the equation must fit the screen (that's why I am not using Stout:

10(Cr(N2H4CO)6)4(Cr(CN)6)3 + 1176KMnO4 + 1399H2SO4 -> 35K2Cr2O7 + 1176MnSO4 + 420CO2 + 660KNO3 + 223K2SO4 + 1879H2O

nor Blakley:

88H2 + 15Ca(CN)2 + 6NaAlF4 + 10FeSO4 + 3MgSiO3 + 6KI + 2H3PO4 + 6PbCrO4 + 12BrCl + 3CF2Cl2 + 20SO2 -> 6PbBr2 + 6CrCl3 + 3MgCO3 + 6KAl(OH)4 + 10Fe(SCN)3 + 2PI3 + 3Na2SiO3 + 15CaF2 + 79H2O

nor this nice oxidation example:

10K4Fe(CN)6 + 122KMnO4 + 299H2SO4 -> 162KHSO4 + 5Fe2(SO4)3 + 122MnSO4 + 60HNO3 + 60CO2 + 188H2O
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Offline Mitch

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Re: going in circles when balancing equation
« Reply #21 on: April 21, 2006, 05:13:37 PM »
Those look like great extra credit questions for chem studesnts. ::Evil grin::
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Offline Borek

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Re: going in circles when balancing equation
« Reply #22 on: April 21, 2006, 05:53:26 PM »
K3[Fe(SCN)6] + 16Na2Cr2O7 + 58H2SO4 -> Fe(NO3)3 + 16Cr2(SO4)3 + 6CO2 + 58H2O + 16Na2SO4 + 3KNO3

EBAS rulez ;)
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Offline Will

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Re: going in circles when balancing equation
« Reply #23 on: May 06, 2006, 08:54:01 PM »
I found all the equations above (not Boreks' directly above!) relatively easy. Here are a couple which I had to balance in this year's UK Chemistry Olympiad competition, which I got a Ag in :'( (missed the Au by a couple of marks :'(), but I was happy to get these right :):
NH3 + NO --> N2 + H2O
NH3 + NO2 --> N2 + H2O
I found them easy but harder than a couple on this page so I thought I might as well mention them!

I came across this equation while messing around with a chemistry experiment simulation program (called CrocChem I think):
Zn + HNO3 --> H2O + N2O + NO + Zn(NO3)2
I checked this reaction out online and different reactions happen with Zn and HNO3 in different conditions, so this equation may not be very accurate. I haven't tried to balance it myself because I've already seen the coefficients so its hard to try to balance it without 'cheating'! I'm sure most of you will find it easy to balance ;).
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Offline Borek

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Re: going in circles when balancing equation
« Reply #24 on: May 07, 2006, 04:07:40 AM »
Quote from: will17 on May 06, 2006, 08:54:01 PM
Zn + HNO3 --> H2O + N2O + NO + Zn(NO3)2

4Zn + 10HNO3 -> 5H2O + N2O + 4Zn(NO3)2
3Zn + 8HNO3 -> 4H2O + 2NO + 3Zn(NO3)2

http://www.chembuddy.com/?left=balancing-stoichiometry&right=balancing-failure

(read the section about KClO3 and HCl).
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Offline lemonoman

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Re: going in circles when balancing equation
« Reply #25 on: May 07, 2006, 04:59:28 AM »
Quote from: Borek on April 21, 2006, 04:55:20 PM
88H2 + 15Ca(CN)2 + 6NaAlF4 + 10FeSO4 + 3MgSiO3 + 6KI + 2H3PO4 + 6PbCrO4 + 12BrCl + 3CF2Cl2 + 20SO2 -> 6PbBr2 + 6CrCl3 + 3MgCO3 + 6KAl(OH)4 + 10Fe(SCN)3 + 2PI3 + 3Na2SiO3 + 15CaF2 + 79H2O

I can't imagine a situation in which you'd need to balance this monstrosity.  In real life, you only balance single reaction steps and then add them all together to get a big overall equation like this.  Or am I wrong?
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Offline Borek

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Re: going in circles when balancing equation
« Reply #26 on: May 07, 2006, 06:34:53 AM »
Quote from: lemonoman on May 07, 2006, 04:59:28 AM
I can't imagine a situation in which you'd need to balance this monstrosity.  In real life, you only balance single reaction steps and then add them all together to get a big overall equation like this.  Or am I wrong?

Exam with mad teacher? ;)

I believe it was an example of how efficient algebraic method of equation balancing is, in the paper published by GR Blakley in JCE  in 1982 (never seen original paper though so I can be wrong).
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Offline Will

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Re: going in circles when balancing equation
« Reply #27 on: May 07, 2006, 09:25:57 AM »
Quote from: Borek on May 07, 2006, 04:07:40 AM
4Zn + 10HNO3 -> 5H2O + N2O + 4Zn(NO3)2
3Zn + 8HNO3 -> 4H2O + 2NO + 3Zn(NO3)2

The simulator went for the 2A + B equation! (11Zn + 28HNO3 --> 14H2O + 2N2O + 2NO + 11Zn(NO3)2)

I wonder if you asked a group of students to balance: HNO2 + HN3 --> N2 + N2O + H2O, how many would come up with: 2HNO2 + 4HN3 --> 6N2 + N2O + 3H2O!
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Offline lemonoman

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Re: going in circles when balancing equation
« Reply #28 on: May 07, 2006, 12:04:07 PM »
Quote from: will17 on May 07, 2006, 09:25:57 AM
I wonder if you asked a group of students to balance: HNO2 + HN3 --> N2 + N2O + H2O, how many would come up with: 2HNO2 + 4HN3 --> 6N2 + N2O + 3H2O!

Personally, I would not have come up with that answer.  I would have stopped right at the beginning, because it's already balanced...

HNO2 + HN3 --> N2 + N2O + H2O

2 H , 4 N , 2 O on left side
2 H , 4 N , 2 O on right side

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Offline Will

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Re: going in circles when balancing equation
« Reply #29 on: May 07, 2006, 12:25:19 PM »
Quote from: lemonoman on May 07, 2006, 12:04:07 PM
Personally, I would not have come up with that answer. I would have stopped right at the beginning, because it's already balanced.

Yup!

Is the 'other' reaction thats happening/could happen: HNO2 + 3HN3 --> 5N2 + 2H2O?
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