Answer:
Molecular formulas describe the exact number and type of atoms in a single molecule of a compound. The constituent elements are represented by their chemical symbols, and the number of atoms of each element present in each molecule is shown as a subscript following that element's symbol.
Le déplacement est défini comme la distance entre la position initiale et finale du corps. Après un tour complet, la terre revient à sa position initiale. La distance entre la position initiale et la position finale est donc nulle.
Le déplacement de la terre est donc nul. Par conséquent, la déclaration donnée est vraie.
Answer:
The final volume 
Explanation:
between work ( w), pressure ( P ) and volume ( V ) is the following:
w=−PΔV
where,
ΔV=V2−V1
It was stated that the gas is expanding, then the work is done by the system and it is of a negative value .
Note that work, should be expressed in 1L⋅atm=101.3J
CHECK THE ATTACHMENT FOR DETAILED EXPLATION
Some Gases are lighter than air
Remember,Air is a mixture of gases
So you cant tell!
It depends on the gas
Hope i helped