July 04, 2022, 10:28:26 AM
Forum Rules: Read This Before Posting

### Topic: oxidation states  (Read 8856 times)

0 Members and 1 Guest are viewing this topic.

#### mrstrh

• Guest
##### oxidation states
« on: September 30, 2004, 12:12:02 AM »
CH3COOH
CH3CNO
CH2CO
C2H5OH

i am trying to find the oxidation number for carbon in each of these. in the first one i think the oxidation is
-3 and the secondproblem it is -3 and the third problem is -2. i dont know if i am doing this right but if some one can help i would appreciated it i also would like someone to explain how to find the oxidation numbers on  larger problems like these.thanks

#### Tetrahedrite

• Guest
##### Re:oxidation states
« Reply #1 on: September 30, 2004, 12:16:48 AM »
Carbon almost exclusively has an oxidation state of +4 in simply organic compounds

#### mrstrh

• Guest
##### Re:oxidation states
« Reply #2 on: September 30, 2004, 12:28:37 AM »
yes it has+4 in normal states up it number can change because it goes from +4 to -4

#### Tetrahedrite

• Guest
##### Re:oxidation states
« Reply #3 on: September 30, 2004, 01:31:03 AM »
Yes, it can have a -4 state eg CO2, but in all examples u have given the oxidation state is +4. The third compound doesn't seem like a compound that would be very stable, is this a typo?

#### AWK

• Retired Staff
• Sr. Member
• Posts: 7982
• Mole Snacks: +555/-93
• Gender:
##### Re:oxidation states
« Reply #4 on: September 30, 2004, 01:42:07 AM »
Oxidation state is a formal number because we should use a few rules, sometimes contradictory with our understanding of periodic table and electronegativity.
Only two rules are absolutely valid:
1. Sum of oxidation states is equal to 0 for molecule (or to charge of ion for ion).
2. Oxidation state for elements is always 0.
The other rules based on periodic table and electronegativity are not absolutely valid, so I may found my private rules just for one or more reactions, assuming that rules 1 and 2 are fullfilled.
Usually, For O oxN=-2 and for H OxN=+1 (on the basis of periodic table and electronegativity)
CH3COOH for C OxN=0
CH3CNO for C OxN=+1 (for N oxN=-3 assumed)
CH2CO for C OxN=0
C2H5OH for C Ox=-2

But someone who solves equation, eg:
Cr2P2O7 + I2 = Cr2O3 + CrP3O9 + PI3
using periodic table and electronegativities can be called Master of Oxidation Numbers
With private rules it is almost as easy as C+O2=CO2

« Last Edit: September 30, 2004, 01:49:32 AM by AWK »
AWK

#### movies

• Organic Minion
• Retired Staff
• Sr. Member
• Posts: 1973
• Mole Snacks: +222/-20
• Gender:
• Better living through chemistry!
##### Re:oxidation states
« Reply #5 on: September 30, 2004, 12:47:49 PM »
I thought CO2 was C4+?  Isn't oxygen always 2- except in ozone?

#### Mitch

• General Chemist
• Administrator
• Sr. Member
• Posts: 5297
• Mole Snacks: +376/-3
• Gender:
• "I bring you peace." -Mr. Burns
##### Re:oxidation states
« Reply #6 on: September 30, 2004, 06:02:28 PM »
CARBON IS NOT ALWAYS +4 IN ORGANIC CHEMISTRY!!!

Take something like C2H4, a double bond. The Carbon has an oxidation state of +2. Then look at ethane C2H6. Now carbon has an oxidation state of +3. Carbon lossed an electron, so it was oxidized. That is why we say we oxidized a molecule when we break-up the double bond. And that is why we say, "we reduced" when we form double bonds.
Most Common Suggestions I Make on the Forums.
1. Start by writing a balanced chemical equation.
2. Don't confuse thermodynamic stability with chemical reactivity.
3. Forum Supports LaTex

#### Tetrahedrite

• Guest
##### Re:oxidation states
« Reply #7 on: September 30, 2004, 08:23:02 PM »
You are correct, my apologies!