Four balloons of equal size are each filled with a gas under one of the following conditions: A) Hydrogen gas at room temperature, B) Hydrogen gas.. at 0 deg. C, C) Clean air at room temperature, D) Clean air at 0 deg. C. Which of these balloons will shrink the fastest?

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.

And a) oxygen i believe