Cellular respiration lab

hi do u have sample lab report for photosynthesis lab with graphs

Which is my control group? 

The third one.

The presoaked are more acidic, correct?!

Yes.

The lab involves three beakers.  One with 50 soybeans that have been pre-soaked for 24 hrs., one with 50 dry beans and one with no beans.  Then bromothymol blue is added to Dixie cups and set in each beaker, beaker is covered with plastic and a rubber band for a tight seal.  How long will it take for the bromothymol blue to react and change color?  Mine didn't change.  Not sure why!  I know the acidic one should've turned yellow and the base (no beans) should stay blue but am not sure why the color didn't change.  How long should it have taken for them to change color and what colors should all three have been?  Are my assumptions correct?

Hi, welcome to the forum.

The production of CO2 during respiration can be measured, as you know, using bromothymol blue. CO2 combines with H2O to form H2CO3 which liberates H+ ions, changing the pH of the solution. Bromothymol blue is blue in pH solutions higher than pH 7.6. It is green in a neutral solutions and yellow in pH solutions less than pH 6.2. When you covered the beans, were the cups sealed correctly?

I put a double layer of saran wrap on top of each beaker and then a rubber band around it.  It must not have been a tight seal...nothing happened and I checked every 30 minutes for 3 hours.     How long does it normally take the bromothymol to change color?

It was just a suggestion, but it shouldn't take that long. However, if the bean had germinated (i.e. had a leaf, cellular respiration should occur and it should turn yellow if it is sealed properly). Your best bet is to report what you observed and try to explain why.

Thanks bio_man!

Glad I could help

Nope i do not have yet..