Depends. Water vapor for example is a gas. When water vapor condenses in the atmosphere, it comes back as precipitation (rain, liquid). When liquid becomes too hot, it evaporates into gas. When gas becomes too hat, it becomes plasma. When liquid becomes too cold, it becomes a solid.
When cooled gases change to liquids (usually) and then solids Solids don't change to gases upon cooling
All gases can be caused to change state to liquids. By either cooling, compression or a combination of both, any gas can be liquefied. This change is a physical change, by the way.
It change the toxic gases into non toxic gases (that are exhausted)
Gases change their volume according to the container that they are in. Liquids change shape but not volume, and solids change neither shape nor volume.
Gases
yes they can
Gases can change volume because they take up the whole space of the container, room, etc. that they are contained in.
When did people start to change the atmosphere by releasing gases
No, the main gases responsible for climate change are actuallyCarbon dioxideMethane gasNitrous Oxide
Yes, it is correct.
Condensation and then freezing.
Gases can NOT change shape because gases don't have a 'shape', it's the container in which they are held that has a shape)