<span>
At the Earth's surface, warm air expands and rises, creating
what is known as an area of low pressure.
Cold air is dense and sinks to the surface to create what is
known as an area of high pressure.</span>
If he feels like, is interested in it, and is able to grasp it, then why not ? Why not indeed ?
Both, there are two different types of molecules to distinguish that
Because of the rule of mask.
You got the formulas on the sheet on the top :) So just use those, exchanging v (as in velocity, expressed in m/s) and the d (in meters) and t (in seconds). Hope you will manage it.