posted by Madison on .
The question I am having trouble with is:
Scientists originally were uncertain whether the oxygen gas produced during photosynthesis came from CO2, H2O, or from both. How could radioisotope tracers be used to settle that question?
Chemistry - DrBob222
6CO2 + 6H2O ==> C6H12O6 + 6O2
Make O in CO2 radioactive; see where the radioactive O is at the end.
Make O in H2O radioactive; see where the radioactive O is at the end.
I'm sorry DrBob, I still don't understand what I am supposed to do. I wrote out the equations, but when you say to make the certain elements reactive, I'm not sure what you mean. Thank you for helping me!
The idea is to use an isotope of O or make O radioactive and use that to produce CO2 or H2O (that is make O different so you can find it). Then (if you made O radioactive) measure the glucose and the O2 and see if the O2 is radioactive or if the glucose is radioactive. Let's say you make some radioactive O and use that to make CO2. Go through the process of photosynthesis, measure with a radioactive counter the glucose and the O2. If the O2 comes from the CO2, the O2 produced by photosynthesis will be radioactive. Repeat using H2O that has radioactive O incorporated in it. It's the same thing as hiding a radioactive pellet in your clothes. A person with a Geiger counter can wave a "counting wand" over your clothes and see where the radioactive pellet has been hidden.