An atmosphere is a sort of shell of gases surrounding a planet or a moon. In Earth's case, we call these gases air. So you could say that the atmosphere is made of air.
There is no atmosphere in space. As such, there is no air. It is often referred to as empty space or alternately dark matter. There is a good article at the site in the related links.
The absence of atmosphere is called a vacuum.
it is in the air but you cant see it
Clouds, fog or mist.
It is called the humidity of the atmosphere.
They often introduce dust particulates to the air.
The weight of air is generally referred to as air pressure (about 14.7 psi). This is the weight oa coulmn of air extending from the surface to the upper limits of the atmosphere for each square inch of surface.
Swallows flying in the air are often referred to simply as "swallows." These agile birds are known for their graceful flight patterns and acrobatic movements as they search for insects.
Air is the atmosphere.
It is often called the safety flame, (often referred to as put it on the safety flame).
Cool and dry air is often referred to as high pressure because in atmospheric terms, high pressure systems are associated with sinking air that leads to clear, dry, and stable weather conditions. This type of air mass tends to move down from heights in the atmosphere, creating an area of higher pressure at the Earth's surface.
Yes, window air conditioners require refrigerant, which is often referred to as Freon, for operation.