Terminology, pressure of gas in fluid (quick question)

[rwooduk]

Would it be correct to say the following...

CO₂ for example can change the surface tension of water from 72 mN m−1 to 57 mN m−1 as its pressure changes from 1 to 11 bar.

I'm used to dealing with concentrations, in fact I would like to change bar to volume percent if anyone has a free moment and might suggest a method and the values I would need.

Thanks for any help with this.

 

[BvU]

Check the context (reference?): it seems to me they may refer to the CO₂ pressure above the water.

 

[rwooduk]

Check the context (reference?): it seems to me they may refer to the CO₂ pressure above the water.

Hm, here is the paper (info given about 1/4 down the abstract):

http://www.sciencedirect.com/science/article/pii/S0021979796902726

Also

A sensitive pressure transducer capable of resolving one part in a hundred thousand was connected into the pipework, and enabled accurate measurement of the absolute pressure, while a similarly accurate external barometer allowed us to record the atmospheric pressure.

It does say 1 to 11 bar absolute, would that that give any indication as to whether it's the pressure in the water or above? I assumed (which is why I wasn't sure of the context) that if a liquid is pressurised with gas then that would indicate how much is in there (partial pressure?) is that incorrect?

 

[BvU]

I'm convinced it's the pressure of CO2 above the liquid. "how much is in there" isn't expressed in terms of a pressure but in molality, molarity or some similar concentration (e.g. g/100 g solvent). Check out Henry's law.

 

[rwooduk]

I'm convinced it's the pressure of CO2 above the liquid. "how much is in there" isn't expressed in terms of a pressure but in molality, molarity or some similar concentration (e.g. g/100 g solvent). Check out Henry's law.

Ok thanks very much for the help!