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Posted: 11/18/2003 3:35:17 PM EDT
How much CO2 is there in a can of coke?
I need this for a chemistry presintation I gotta do. Im trying opening a can in a bag and letting it go flat, but it would be easier if one of you knew and had a source (proof, it is school after all)
Link Posted: 11/18/2003 5:48:19 PM EDT
I just thought I would ask. Guess no one knows
Link Posted: 11/18/2003 5:52:08 PM EDT
Research the solubility of CO2 in liquid. Measure the temperature and assume a pressure for the contents of the can.
Link Posted: 11/18/2003 5:57:57 PM EDT
Link Posted: 11/18/2003 6:46:08 PM EDT
All I could find was a 'myth' that some colege kid drank 8 cans of coke and collapsed in a soda drinking contest. People are so stupid sometimes.

Sorry.


ByteTheBullet (-:
Link Posted: 11/18/2003 6:47:50 PM EDT
Check this site, it sounds like what you are doing...www.cockeyed.com/inside/coke/coke.html


ByteTheBullet (-:
Link Posted: 11/18/2003 6:55:27 PM EDT

The solubility of CO2 in *water* at 20*C (room temperature) is 88ml/100ml water at one atmosphere (760mmHg). A coke can has 355ml of water (well, sugar and water, so I'll get to that below). Therefore, a can of coke would contain 88ml/100ml water X 355ml water= 312.3ml of CO2. But, you are dissolving the CO2 in a solution of primarily sugar in water and the solubility would be less. Also, the pressure in the can is probably several atmospheres.

Let's say the two cancelled each other out (less CO2 because of sugar in solution but more CO2 because of increased pressure) you could guesstimate 312ml of CO2 in a can of coke. All the above info is from The Merck Index, Eleventh Edition.

Your teacher is trying to make the point that it is somewhat difficult to find an exact answer, and the question is mainly to get you thinking. So think, dammit.
Link Posted: 11/18/2003 7:38:04 PM EDT
[Last Edit: 11/18/2003 7:39:07 PM EDT by JIMBEAM]
c-4

You forgot about the CO2 out of solution in the vapor space of the can.
Link Posted: 11/18/2003 7:50:21 PM EDT
That website is hilarious!
Link Posted: 11/18/2003 7:56:39 PM EDT

Originally Posted By JIMBEAM:
c-4

You forgot about the CO2 out of solution in the vapor space of the can.



I know, I know. You'd have to account for both an increased solubility of CO2 in water when there is pressure above the liquid and the actual CO2 gas above the liquid. It's a never-ending problem. I think the teacher basically wanted the students to find every possible variable.
Link Posted: 11/18/2003 7:56:56 PM EDT

Originally Posted By JIMBEAM:
c-4

You forgot about the CO2 out of solution in the vapor space of the can.



Yeah, but that's pretty minimal compared to the (much denser) liquid carbonic acid in the can. All in all, it's an annoying problem because you need to know the pressure in the can and the concentrations and solubilities of all the other dissolved substances (primarily sugars).
Link Posted: 11/18/2003 8:09:54 PM EDT
Link Posted: 11/18/2003 8:14:52 PM EDT
I can tell you exactly how much CO2 it takes to explode a plastic soda bottle.


4 chunks -Sounded like a .45 went off in my kitchen. Scared the bejezzus out of my wife.
I do not recommend it indoors.
Link Posted: 11/18/2003 8:34:47 PM EDT
There is no pressure in a can of Coke. Untill
you shake it. It is filled at one atmosphere and sealed at the ambient temperature in the factory.
It has no internal pressure unless you shake it or heat it.
The only thing that increases pressure after bottling are sparkling wines or champagne due to continuing fermentation.
Link Posted: 11/18/2003 8:42:38 PM EDT

Originally Posted By captainpooby:
There is no pressure in a can of Coke. Untill
you shake it. It is filled at one atmosphere and sealed at the ambient temperature in the factory.
It has no internal pressure unless you shake it or heat it.
The only thing that increases pressure after bottling are sparkling wines or champagne due to continuing fermentation.



That would explain the "Pffftt!" air sound when I open a can... oh wait no it doesn't?
Link Posted: 11/18/2003 8:46:09 PM EDT

Originally Posted By SNorman:

Originally Posted By captainpooby:
There is no pressure in a can of Coke. Untill
you shake it. It is filled at one atmosphere and sealed at the ambient temperature in the factory.
It has no internal pressure unless you shake it or heat it.
The only thing that increases pressure after bottling are sparkling wines or champagne due to continuing fermentation.



That would explain the "Pffftt!" air sound when I open a can... oh wait no it doesn't?



That sound is likely from CO2 that has dissolved out of the liquid by agitation...
Link Posted: 11/18/2003 8:48:02 PM EDT

Originally Posted By SNorman:

Originally Posted By captainpooby:
There is no pressure in a can of Coke. Untill
you shake it. It is filled at one atmosphere and sealed at the ambient temperature in the factory.
It has no internal pressure unless you shake it or heat it.
The only thing that increases pressure after bottling are sparkling wines or champagne due to continuing fermentation.



That would explain the "Pffftt!" air sound when I open a can... oh wait no it doesn't?




By handling the can or opening it at a higher temp than it was filled you have created different conditions than what the can was filled under.
Remember, the can or bottle was poured full of liquid, not filled like a SCUBA tank with a compressor. Think about it.
Link Posted: 11/19/2003 4:37:04 AM EDT

Originally Posted By captainpooby:
There is no pressure in a can of Coke. Untill
you shake it. It is filled at one atmosphere and sealed at the ambient temperature in the factory.
It has no internal pressure unless you shake it or heat it.
The only thing that increases pressure after bottling are sparkling wines or champagne due to continuing fermentation.



I wouldn't say there's no pressure. Carbonic acid (H2 C O3) has a very high vapor pressure. The pure liquid produces a pressure of 56 times atmospheric at room temperature in a sealed container. No matter how nice you are to that coke can, it is going to pop when you open it.
Link Posted: 11/19/2003 5:23:18 AM EDT
As I understand it the problem with CO2 in coke is that it tingles the nose of the people who snort it.
Link Posted: 11/19/2003 6:14:53 AM EDT

Originally Posted By fizassist:

Originally Posted By captainpooby:
There is no pressure in a can of Coke. Untill
you shake it. It is filled at one atmosphere and sealed at the ambient temperature in the factory.
It has no internal pressure unless you shake it or heat it.
The only thing that increases pressure after bottling are sparkling wines or champagne due to continuing fermentation.



I wouldn't say there's no pressure. Carbonic acid (H2 C O3) has a very high vapor pressure. The pure liquid produces a pressure of 56 times atmospheric at room temperature in a sealed container. No matter how nice you are to that coke can, it is going to pop when you open it.



I have firsthand knowledge of the pressure in a coke can: In my instruments class (course required for my ME degree) we fitted a full unopened coke can with a strain gage and then opened it. The pressure difference was approximately 50 psi.

You can feel this experimentally by squeezing the can before you open it. Granted you would presurize it (if it is sealed) as you squeeze it, but you can tell the can is under a bit of pressure. Better yet use a plastic bottle with a screw top: Squeeze it before opening it then open the top but don't drink any then reseal the top and squeeze again. You will feel a distinct difference in the force required to deflect the sides of the bottle between opened and unopened.

I believe fizasist nailled the cause. You fill it at 1 atmospere but the C02 comes out of solution shortly thereafter and pressurizes the can.

Kent
Link Posted: 11/19/2003 7:02:16 AM EDT

Originally Posted By Green_Canoe:

Originally Posted By fizassist:

Originally Posted By captainpooby:
There is no pressure in a can of Coke. Untill
you shake it. It is filled at one atmosphere and sealed at the ambient temperature in the factory.
It has no internal pressure unless you shake it or heat it.
The only thing that increases pressure after bottling are sparkling wines or champagne due to continuing fermentation.



I wouldn't say there's no pressure. Carbonic acid (H2 C O3) has a very high vapor pressure. The pure liquid produces a pressure of 56 times atmospheric at room temperature in a sealed container. No matter how nice you are to that coke can, it is going to pop when you open it.



I have firsthand knowledge of the pressure in a coke can: In my instruments class (course required for my ME degree) we fitted a full unopened coke can with a strain gage and then opened it. The pressure difference was approximately 50 psi.

You can feel this experimentally by squeezing the can before you open it. Granted you would presurize it (if it is sealed) as you squeeze it, but you can tell the can is under a bit of pressure. Better yet use a plastic bottle with a screw top: Squeeze it before opening it then open the top but don't drink any then reseal the top and squeeze again. You will feel a distinct difference in the force required to deflect the sides of the bottle between opened and unopened.

I believe fizasist nailled the cause. You fill it at 1 atmospere but the C02 comes out of solution shortly thereafter and pressurizes the can.

Kent


If you read my post. Thats what I said. The CO2 comes out of solution by heating or handling "after" bottling.,
Link Posted: 11/19/2003 8:31:52 AM EDT
Hey green canoe, ME is what Im heading for.

What do you do for a living?
Link Posted: 11/19/2003 2:56:00 PM EDT

Originally Posted By captainpooby:
If you read my post. Thats what I said. The CO2 comes out of solution by heating or handling "after" bottling.,



I guess my point was that you don't have to heat it or even handle it. You could bottle it, leave it at the same temperature, and never touch it, and it would still have a higher pressure than the surrounding air. C02 is much happier as a gas. Sorta like Nitrogen. BOOM
Link Posted: 11/19/2003 4:07:46 PM EDT
I went to Retired_Navy's link and sent the question.

I just got an answer back, so I thought I would share what I found out.

"Thank you for contacting The Coca-Cola Company, Mr. Short. We appreciate
the opportunity to answer your questions about carbonation.

Carbonation is measured in "volumes." The traditional method for
measuring CO2 levels in soft drinks is as follows: You must first use a device
called the Zaha-nagel Device. The bottle closure or can closure is pierced and
a probe is placed into the head space of the package. The package is then
shaken and the pressure in the head space is measured and recorded. Then the
temperature of the product is measured and recorded. Next you must refer to
the "Table of Solubility of CO2 in Water." Find the temperature and
pressure measurements on the table and that will give you the corresponding
volumes of CO2.

Carbonation is the incorporation of carbon dioxide into water. In soft drinks,
carbon dioxide produces the distinctive "sparkling" quality and a
"bubbling" effect as the drink is poured from the container. The
bubbling of carbonated drinks has to do with the surface tension. Surface
tension is a physical attraction between the surfaces of two substances. The
presence of ice increases the surface area, thereby causing more bubbling.

CO2 is a gas that is dissolved. A gas escapes whenever it is agitated or moved
around. The temperature of the beverage will determine how much carbonation
can be dissolved into the beverage. More gas will remain in solution in a cold
beverage than in a warm or hot beverage. Cans are filled under pressure to
keep the beverage carbonated at a specific level.

Bubbles of gas can form along the surface of the can (the number of bubbles
depends on many things including the microscopic smoothness of the can). If
there are a lot of bubbles in the liquid as compared to the headspace, foaming
will occur when the can is opened. Tapping the can may release these
microscopic bubbles and they will either go back into solution in the beverage
or become part of the headspace gas.

The target level of carbonation in Coca-Cola classic is 3.2 - 4.2 (measured in
volumes).

We hope this helps to answer some of your questions. If you have additional
questions or comments, please visit our Web site again.

Sheila
The Coca-Cola Company
Industry and Consumer Affairs"
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