The term that is used to label the energy levels of electrons are principle quantum numbers and a valance band refers to the “energy levels in an atom where the electrons that participate in bonding occupy. These energy levels correspond to those of the s and p orbitals of the outermost shell of the atom being considered.” Hope this helps! :)
d. atomic mass unit is your answer.
I would say A because they are two or more different elements bound chemically together and can only be separated chemically.
The carbon dioxide in the headspace above the liquid is at higher pressure than atmospheric pressure outside the can.
The gas is at a lower volume initially but suddenly has a larger volume available when the can is opened.
The change in pressure as the gas rapidly moves to become dispersed through its new volume causes the "whoosh" sound.
The gas law that applies is Boyle's law.
This above is the exact answer for edgunity