Chemistry help?

I never had any chemistry. I'm working on a project that involves some.

I need to understand what O- means. I know O is oxygen. But I don't know what the + and - things are.

The context is photocatalysis. "Photonic energy catalyses the breaking of ambient oxygen and water vapor molecules into O- and -OH (hydroxyl) molecules." I'm researching hydroxyls, and I've got the intellectual understanding, but not the chemical thing.

positive and negative charges

Now the only chemistry I've ever had is waht I've picked up in biology classes, BUT I belive what your referring to is a charged atom of oxygen also known as an ion. IT can affect how a compound reacts chemically. Here is a link to info on Ions:

http://en.wikipedia.org/wiki/Ion


I don't think it will greatly affect your research if you don't know the ins and outs of how ions work and how it affects how atoms bond together, but thats for you to decide I hope I helped!

Originally Posted by LDG

I never had any chemistry. I'm working on a project that involves some.

I need to understand what O- means. I know O is oxygen. But I don't know what the + and - things are.

The context is photocatalysis. "Photonic energy catalyses the breaking of ambient oxygen and water vapor molecules into - and -OH (hydroxyl) molecules." I'm researching hydroxyls, and I've got the intellectual understanding, but not the chemical thing.

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Basically, "-" means you have an extra electron, and "+" means you are missing one.
Imagine the molecule of water, for example, you want to break - in vapor
H-O-H, now imagine a set numbers of electrons, who keep the atoms in this molecule together, keep moving back and forth really fast... The whole molecule is neutral, but when you split it, one side will have more electrons, and the other will be missing some (since you don't create electrons) - in this specific case, one side will have one more (marked with "-"), and the other will be missing one (marked with the symbol +).
So, you will be left with H+ OH-.... do I make any sense?

THANK YOU. That's exactly what I needed to know.

Carolina - I think you're right except I think you've got the "+" and "-" backwards. What you wrote makes complete sense - if the "-" means it's missing an electron and "+" means it has an extra one. I know for sure that -OH (hydroxyl radicals) are missing an electron. It's why they're so reactive, and why they're far more oxidative than bleach or hydrogen peroxide, as those contained paired electrons.

I'm also guessing that if the + or - is to the right of the molecule designation, it's an ion, and if it's to the left, it's a radical.

Originally Posted by LDG

THANK YOU. That's exactly what I needed to know.

Carolina - I think you're right except I think you've got the "+" and "-" backwards. What you wrote makes complete sense - if the "-" means it's missing an electron and "+" means it has an extra one. I know for sure that -OH (hydroxyl radicals) are missing an electron.

It's why they're so reactive, and why they're far more oxidative than bleach or hydrogen peroxide, as those contained paired electrons.

I'm also guessing that if the + or - is to the right of the molecule designation, it's an ion, and if it's to the left, it's a radical.

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I think she had it right. If "-" meant you were missing an electron, that would make it positive. Think about it. If you have something with say, 6 electrons and 6 protons, when one electron is missing you have 6 protons and 5 electrons, making it positive. So, "+" would mean a missing electron. Missing electrons give a positive charge, "+" and extra electrons give a negative charge, "-".

Now that I know how to look it up, I will. But "-OH" is definitely the symbol for an hydroxyl radical, and I know they're missing an electron, and that's also what makes me think that the "-" symbol being on the left indicates a radical as opposed to an ion.

Could it be that the - is indicating where the rest of the compound binds to the hydroxyl group? I say this because when your writing out a chemical compound you use - to indicate bonds:

http://en.wikipedia.org/wiki/File:Alcohol_examples.gif

Sorry to keep siting Wikipedia but I'm using it to back up what I'm remembering from my classes

Well, I know I'm definitely wrong.

And Danielle, you may be right. Apparently a radical is usually designated as the chemical symbol with a dot after it.



Radicals are: atoms, molecules, or ions with unpaired electrons, and they can have positive, negative, or zero charge.

So I don't know why this one is being written as -OH.

(No wonder I never took chemistry. ).

Oh - and Carolina, you're right about the negative and positive charge.

But apparentaly a radical by definition has one non-paired electron, but it can still (somehow) have a positive, neutral, or negative charge.

Laurie, I didn't want to put it here.... But I do have a degree in Chemistry I am right

This is what I'm putting myself in for (Majoring in chemistry )

Originally Posted by Tara & Rob

This is what I'm putting myself in for

(Majoring in chemistry )

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It is a tough one! I gotta say, it's been many years since I touched anything related to chemistry... 1996 was the last time to be exact! I still see things differently though, that is for sure - 5 years of university, at least that you would hope, right? But I forgot the majority... Man, when I think I studied incredibly hard for soooo long... wow

So Carolina, what does it mean when the "+" or "-" is BEFORE the chemical abbreviation as opposed to after it?

I don't understand ANY of this. LOL No wonder I barely passed Chemistry in high school. The only reason I passed was b/c the teacher didn't want me in his class again. Seriously. Give me Biology any day.

Originally Posted by LDG

So Carolina, what does it mean when the "+" or "-" is BEFORE the chemical abbreviation as opposed to after it?

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Laurie, there is only one possibility: It is the same thing, OR you are looking at a reaction, such as below. BUT if you are looking at this: +H, it is the same as this H+
O2− + H2O → 2 OH−

Laurie, one more thing that might make it easier to think about this:
Think about Electrons as electricity, as electric charge... Electrons have the symbol "-".
So, if you have one more electron, you are electrically charged, therefore the symbol "-". If you are missing an electron, your atom is positively charged, therefore the symbol "+".
In our brain, we have the tendency to think more electrons, mark +... But actually, more electrons, means an electric charge, so... "-"!
When you see 2- it means you have two extra electrons floating around that atom or molecule. When you see 2+, means you are missing 2 electrons.
Since atoms and things in nature alike are always looking to be neutral, these ions ("+" and "-") are highly unstable and will react to another "+" or "-".
One "+" will react with a "-" making a neutral molecule... that is the case of H+ + OH- = H2O

From what I remember of my most recent chemistry class, and from what I've learned of amino acids in cell biology class- and amino acids all have something called a functional group in their structure, which is what hydroxyl also is, the "-" before the -OH simply indicates the bond that forms whenever OH bonds to another molecule. It can also be written as :OH.

Originally Posted by ut0pia

From what I remember of my most recent chemistry class, and from what I've learned of amino acids in cell biology class- and amino acids all have something called a functional group in their structure, which is what hydroxyl also is, the "-" before the -OH simply indicates the bond that forms whenever OH bonds to another molecule. It can also be written as :OH.

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Well, if it is a long line, yes, but the "+" wouldn't make sense in this case...

Yea, it would make absolutely no sense if there is a + before, but I just wanted to throw it out there since she said she's researching hydroxyls and maybe that's what's confusing her. I meant a long line, I just couldn't find it on my keyboard lol..