Re: CO2, O2 diffusion rates
---------- Forwarded message ----------
From: psears at emr1_NRCan.gc.ca (Paul Sears)
Subject: Re: CO2, O2 diffusion rates
To: Aquatic-Plants at ActWin_com
Date: Mon, 24 Feb 1997 09:32:34 -0500 (EST)
> From: krombhol at felix_teclink.net (Paul Krombholz)
> Subject: Re: Homework Assignment
> However, I am pretty sure that CO2 also
> diffuses faster, because it can diffuse in several forms (dissolved CO2,
> carbonic acid, and bicarbonate ion). Chemists: back me up! I'm too old
> and feeble to look up solubilities and diffusion rates. Thanks.
It may diffuse faster, but I'm not impressed by the argument above.
In water, only about 1/500 part of the CO2 exists as carbonic acid, and
the transition reaction is very slow (by chemical standards). I think
the diffusion of CO2 will be decided by the diffusion of the CO2 itself.
Its higher solubility may help, because you may be able to get a bigger
concentration gradient, and thus faster transport even if the diffusion
coefficient is lower. It may be lower, the molecular weight of CO2 is
higher, and neither molecule has a dipole.
Paul Sears Ottawa, Canada
Finger ap626 at freenet_carleton.ca for PGP public key.