# How to calculate?

1. Nov 7, 2006

### Andre

In the good old days of the 19th century, carbon dioxide levels of the air were measured in various chemical ways. Several methods required drying of the air first. This could be accomplished by leading the air through sulphur acid (H2SO4). However it appears that CO2 also dissolves partly in that process.

Now, I'm sure that there are methods of estimating the amount of CO2 that dissolves this way and consequently, the magnitude of the induced error, something with a Bunsen adsorption coefficients. But I'm afraid I did not pay enough attention in highschool, some millenium or so ago.

Anybody, who can help me out?

2. Nov 7, 2006

### Bystander

Everything is soluble in everything else. How soluble? You're stuck with measuring. Volume of air sample? Volume of acid used to dry the air sample? Did they just pump air through the acid until it reached steady state with the exception of water loss?

3. Nov 8, 2006

### Andre

Well let's say that they pumped N moles or air through a volume V of acid with an initial CO2 partial pressure of p1 at a termperature T and a total pressure P. What would be the remaining CO2 partial pressure p2? Would the difference between p1 and p2 be significant or negliglible?

4. Nov 8, 2006

### Bystander

Still not constrained: are you equilibrating "dN" at a time with "V," or "N" all at once with "V?" You see the difference? First case, you can take the tag end of "N" for analysis, and the difference can be driven to a limit of 0 regardless of solubility; second case, the difference is a function of only the solubility.

Measurements on CO2 solubility in H2SO4? Gotta be in the literature somewhere --- sorta thing people would have done between the wars. Finding it? CA wasn't indexing "systems: x + y" in those days --- gonna be a little tough. Significant? No --- there'd be a ton of information on how to control it for all the industrial applications.

Quick means to estimate? Measured amount of baking soda in measured amount of (dilute --- let's do worst case) sulfuric acid, and measure the evolved gas volume --- it comes up more than 10% less than theoretical, we're gonna have to look a little more closely.