I don’t understand can you please explain your question thank u
Answer:
it cannot be considered a physical change because it occur from the chemical reaction.
Explanation:
because physical change is the change of the size,volume, density,flexibility. in other words its a change in the outer appearance or change in which we can see or feel without using a tool or a machine
hope it help just my opinion
The electrons float around in an outer sub shell
Answer: 21965.517 Pa
Explanation:
Pressure 
is the force 
exerted by a gas, a liquid or a solid on a surface (or area) 
, its unit is Pascal 
which is equal to 
and its formula is:
(1)
In this case we have the surface of a sole of a tennis shoe:
(2)
And the mass 
of the person who wears it:
On the other hand, we know the weight is the force the Earth exerts on people and objects due gravity 
:
(3)
Substituting (2) and (3) in (1):
(4)
Finally:
This is the pressure the shoe exert on the ground
The smallest unit that makes up matter is an atom!
