# Heat Storage Capacity of CO2 molecules

#### Ellsworth

I am a science hobbyist and working on a paper to illustrate the impact of CO2 on Global Warming.

Question – What is the Storage Capacity in joules, of one molecule of CO2 @ 20c/68f/293k. In other words, what is the maximum amount of IR energy that one molecule of CO2 can store at this temperature.

The mass of one molecule of CO2 is 7.308 x 10^-23g or 7.308 x 10^-26kg and the Specific Heat Capacity of CO2 is 834 at constant pressure (J kg-1K-1)

In essence, I am looking for both the value and the formula for which to use in order to calculate this.

For the cherry on top, how long can it store this amount of energy

Last edited:
Related Earth Sciences News on Phys.org

#### mjc123

It is not meaningful to talk of the heat capacity of one molecule. (Why do you want to, anyway?) Heat capacity is a bulk property.

Heat isn't stored in CO2 molecules. When a CO2 molecule absorbs IR radiation it quickly loses the excess energy by collisions with other molecules in the air, so the atmosphere warms up.

#### Ellsworth

Hi M, thanks for the note. I should have properly worded the question to read, "In other words, what is the maximum amount of Electromagnetic IR energy that one molecule of CO2 can store at this temperature. Trying to get the feel for significance of what you described in terms of joules of energy. Thanks Ellsworth

#### DrClaude

Mentor
Hi M, thanks for the note. I should have properly worded the question to read, "In other words, what is the maximum amount of Electromagnetic IR energy that one molecule of CO2 can store at this temperature. Trying to get the feel for significance of what you described in terms of joules of energy. Thanks Ellsworth
That is still strangely worded. A molecule doesn't store "electromagnetic IR energy." Also, it is strange to think about the role of CO2 in the greenhouse effect in terms of heat capacity.

Strictly speaking, the bond-dissociation energy of CO2 is 5.51 eV, so this is more or less the maximum energy a molecule of CO2 could absorb from IR radiation before breaking apart.

Heat isn't stored in CO2 molecules. When a CO2 molecule absorbs IR radiation it quickly loses the excess energy by collisions with other molecules in the air, so the atmosphere warms up.
I would argue that this is not the main factor in the greenhouse effect. It is rather the fact that the CO2 will reemit the IR radiation in all direction, including back towards the surface.

#### russ_watters

Mentor
If CO2 were unusually good at storing thermal energy, it would reduce global warming.

As worded though, it appears to me the answer to the OP's question is zero.

"Heat Storage Capacity of CO2 molecules"

### Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving