Thread: how much heat is given off when co2 in compressed

HI

I was wanting to know how much heat is given off when co2 is compressed and where it is most efficient (where you get the most heat for the amount of energy used to compress it

Are you familiar with the Ideal Gas Law, PV = nRT?

P is the pressure of the gas
V is volume of the gas
n is the amount of gas, in moles (basically a mole is Avogadro's Constant number of gas molecules)
T is the temperature of the gas
and
R is the universal gas constant.

R is the product of Boltzmann's Constant and Avogadro's Constant.

Note that the constitution of the gas is unimportant in this law. For real gases, there are considerations of molecular size (negligible, for CO2) and intermolecular forces (generally weak in any gas-- that is after all why they're gases-- and of ever-decreasing importance as the temperature rises). If you want the differences in behavior of CO₂ and an ideal gas, they're called the "residual properties" of CO₂. I have not tried to look them up but will if you have trouble; just ask. My google-fu is strong, and is at your service.

As for the second part of your question, you weren't specific enough about what exact changes in state you had in mind. If you can give some more details about the system you're thinking of I'll try again.

I had to look up the residual properties of CO₂ to answer a question in another thread, they are in the table on this page:

van der Waals Equation of State

Would u be able to give me a formula that would take co2 at atmospheric pressure and a given temperature and give the temperature increase in relationship to the pressure added.

any help would be greatly appreciated
ps Im only grade 9

where P1, V1 and T1 are the pressure, volume and temperature before compression and P2, V2 and T2 the pressure, volume and temperature after compression.

At ambient conditions,
P1 = 101325 Pa (1 atmosphere)
T1 = 298 K
V1 = 24.5 L (assuming 1 mole of CO2)

If you know the final pressure (P2) and final volume (V2) you can calculate the final temperature (T2) and hence the temperature increase.

Originally Posted by dansam8

HI

I was wanting to know how much heat is given off when co2 is compressed and where it is most efficient (where you get the most heat for the amount of energy used to compress it

It is easy to get 100% of the work energy turned into heat. The difficult part is turning heat energy into work, and that is when you can never get 100% efficiency.

thanks for the help