<span>2 Nitrogen, 4 Hydrogen, 3 Oxygen
9 atoms per molecule.
NH4, ammonium (not to be confused with ammonia NH3) is a 1+ ion and NO3 is 1-.
</span>
If velocity is decreasing, then acceleration is in the direction
opposite to the velocity.
If the object is moving in the direction that you call 'positive',
then acceleration is negative.
What do we know that might help here ?
-- Temperature of a gas is actually the average kinetic energy of its molecules.
-- When something moves faster, its kinetic energy increases.
Knowing just these little factoids, we realize that as a gas gets hotter, the average speed of its molecules increases.
That's exactly what Graph #1 shows.
How about the other graphs ?
-- Graph #3 says that as the temperature goes up, the molecules' speed DEcreases. That can't be right.
-- Graph #4 says that as the temperature goes up, the molecules' speed doesn't change at all. That can't be right.
-- Graph #2 says that after the gas reaches some temperature and you heat it hotter than that, the speed of the molecules starts going DOWN. That can't be right.
--
Answer:
There are two reasons why air pressure decreases as altitude increases: density and depth of the atmosphere. Most gas molecules in the atmosphere are pulled close to Earth's surface by gravity, so gas particles are denser near the surface.
Explanation:
