19th Day of Project

So today we started on the Gas Absorption lab. The professor set up the equipment the day before and we finished all the plumming this morning. We had to connect one tube to carry Oxygen into a glass bulb, and another tube to carry carbon dioxide from the glass bulb into the fume hood. (inhaling Carbon Dioxide in large concentrations can be fatal - makes sense).

The whole point of the of the lab is to blow CO2 into water, then blow air through and measure the conductivity. It depends on how much of the CO2 dissloves, form carbonic acid, and how much of that dissociates into ions.

So, the professor gave me a little lecture on conductivity, resistance and resistivity before we started with the lab. The resistivity is the ability of a material to resist electrical conduction, and is defined using this equation:

p= R*(A/l)

p (rho)= resistivity, R=resistance of the substance, A= cross-sectional area of the substance, l= length of the material/substance

We then started by blowing pure oxygen into the water and I measured the conductivity. From then on we put .5 % of CO2, and 99.5% O2, and measured the conductivity. I then continued the experiment, varying the amounts of CO2 and O2 blown through the water from .5 to 1.00. After blowing through the gases I had to wait for about 10 minutes before measuring the conductivity, and then leaving it for another 10 minutes to take a second reading (to see if the conductivity had changed) before changing the amounts of the gases.

So, tomorrow we'll be continuing the lab with varied percentages of CO2 and O2.