Which one of the following [H+] concentrations represents an acidic solution? A
1.9 x 10–2 M

B
1.8 x 10–8 M

C
1 x 10–7 M

D
3 x 10–14 M

The correct answer is C.

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.