June 24, 2019, 04:31:01 PM
Forum Rules: Read This Before Posting


Topic: Hard Balancing Equation! Please *delete me*  (Read 27828 times)

0 Members and 1 Guest are viewing this topic.

Offline hullio

  • New Member
  • **
  • Posts: 6
  • Mole Snacks: +2/-0
Hard Balancing Equation! Please *delete me*
« on: March 26, 2007, 07:06:15 PM »
Here are two balacing equations which are really hard. I'll be very impressed if someone could balance these! I got these two questions in class and my teacher said that even she couldn't balance (either it can't be possible or she's a total failure).

Cu + HNO3 (concentrated) ----> Cu(NO3)2 + H2O + NO2


and


Cu + HNO3 (dilute) ----> Cu(NO3)2 + H2O + NO

Please *delete me* Thanks.

Offline millerst

  • Regular Member
  • ***
  • Posts: 27
  • Mole Snacks: +1/-0
Re: Hard Balancing Equation! Please *delete me*
« Reply #1 on: March 26, 2007, 07:14:30 PM »
Here they are, not too hard...

1) Cu + 4 HNO3 ---> Cu(NO3)2 + 2 H2O + 2 NO2

2) 3 Cu + 8 HNO3 ---> 3 Cu(NO3)2 + 4 H2O + 2 NO

Offline hullio

  • New Member
  • **
  • Posts: 6
  • Mole Snacks: +2/-0
Re: Hard Balancing Equation! Please *delete me*
« Reply #2 on: March 26, 2007, 07:36:18 PM »
yea they weren't too hard...i think my teacher sucks. i got really stuck on the second one...thank you so much for the quick response! ;)

Offline hullio

  • New Member
  • **
  • Posts: 6
  • Mole Snacks: +2/-0
Re: Hard Balancing Equation! Please *delete me*
« Reply #3 on: March 26, 2007, 08:14:34 PM »
I've another one that I'm getting nowhere at...

Zn + H2SO4 ----> ZnSO4 + H2O + H2S

Also, do you guys have any helpful tips to do these balancing equations quicker/more efficiently?
« Last Edit: March 26, 2007, 08:31:56 PM by hullio »

Offline millerst

  • Regular Member
  • ***
  • Posts: 27
  • Mole Snacks: +1/-0
Re: Hard Balancing Equation! Please *delete me*
« Reply #4 on: March 26, 2007, 08:19:25 PM »
One of your compounds is H20 (20 atoms of H). Did you mean H2O (water)?

Offline hullio

  • New Member
  • **
  • Posts: 6
  • Mole Snacks: +2/-0
Re: Hard Balancing Equation! Please *delete me*
« Reply #5 on: March 26, 2007, 08:31:30 PM »
Yes sorry.

Offline millerst

  • Regular Member
  • ***
  • Posts: 27
  • Mole Snacks: +1/-0
Re: Hard Balancing Equation! Please *delete me*
« Reply #6 on: March 26, 2007, 08:35:22 PM »
4 Zn + 5 H2SO4 ---> 4 ZnSO4 + 4 H2O + H2S

Offline hullio

  • New Member
  • **
  • Posts: 6
  • Mole Snacks: +2/-0
Re: Hard Balancing Equation! Please *delete me*
« Reply #7 on: March 26, 2007, 08:40:37 PM »
Wow thank you! How do you do them so fast? Care to share any tips? This is how I do them:

Zn + H2SO4 ----> ZnSO4 + H2O + H2S

Zn = 1               Zn = 1
H = 2                  H = 4
S = 1                  S = 2
O = 4                 O = 4

Then I just carry on from there. So how do you do them so fast? I guess you're a number type guy lol                         

Offline constant thinker

  • mad scientist
  • Sr. Member
  • *****
  • Posts: 1275
  • Mole Snacks: +85/-45
  • Gender: Male
Re: Hard Balancing Equation! Please *delete me*
« Reply #8 on: March 26, 2007, 09:38:19 PM »
Pay attention to functional groups, like the SO4 (sulfate) group. You can count that as one whole unit sometimes, but in this case it's different. Finding little things like that can help. Practice also helps.
"The nine most terrifying words in the English language are, 'I'm from the government and I'm here to help.' " -Ronald Reagan

"I'm for anything that gets you through the night, be it prayer, tranquilizers, or a bottle of Jack Daniels." -Frank Sinatra

Offline AWK

  • Retired Staff
  • Sr. Member
  • *
  • Posts: 6488
  • Mole Snacks: +466/-79
  • Gender: Male
Re: Hard Balancing Equation! Please *delete me*
« Reply #9 on: March 27, 2007, 02:04:15 AM »
I've another one that I'm getting nowhere at...

Zn + H2SO4 ----> ZnSO4 + H2O + H2S

Also, do you guys have any helpful tips to do these balancing equations quicker/more efficiently?
Take this reaction in a few steps
1. Zn + H2SO4 =  ZnSO4 + H2 This is a simple single replacement reaction
Then think how much H2 you need to reduce H2SO4 to H2S and H2O (answer is 4)
Then join this knowledge together
4Zn +4H2SO4 =  4ZnSO4 +4H2
4H2+ H2SO4 = H2S + 4H2O
and finally
4Zn + 5H2SO4 =  4ZnSO4 + H2S + 4H2O
AWK

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 25073
  • Mole Snacks: +1646/-396
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Chembuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info, pH-meter.info

Offline bigblue17

  • Regular Member
  • ***
  • Posts: 16
  • Mole Snacks: +0/-0
Re: Hard Balancing Equation! Please *delete me*
« Reply #11 on: April 07, 2007, 08:32:03 PM »
hardest balancing equation i have ever seen is as follows

KNO3 + C12H22O11 -> N2 + CO2 + H2O + potassium carbonate ( either KCO3 or KCO4 i forget)

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 25073
  • Mole Snacks: +1646/-396
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re: Hard Balancing Equation! Please *delete me*
« Reply #12 on: April 08, 2007, 03:27:04 AM »
either KCO3 or KCO4 i forget

Neither. K2CO3. 24N2.

Check out this page for a list of reactions to balance:

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

Scroll down for really hard ones.
Chembuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info, pH-meter.info

Offline phoebusvn

  • New Member
  • **
  • Posts: 8
  • Mole Snacks: +0/-0
Re: Hard Balancing Equation! Please *delete me*
« Reply #13 on: April 14, 2007, 11:06:52 PM »
either KCO3 or KCO4 i forget

Neither. K2CO3. 24N2.

Check out this page for a list of reactions to balance:

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

Scroll down for really hard ones.

Thanks for the website. it is good for practicing.

Sponsored Links