The single-charge difference would result in a difference in mobility in a normal experiment (which separates chains based on size), but would make a detectable difference in pI.

I’m not sure what your trying to say here.. can you clarify again?

Aphysical change is one that you can put in and remove like a ham sandwich. the stuff you put in there can be changem its not permanet. a chemical change is on that can't be change thats permanet. like when you make a cake and bake it. you can't get those ingredients back.

Decomposition is the cycle at which bacteria breaks down any organic material into the soil