The chemical formula of a compound is an expression that stares out the elements (in form of symbols)present in a compound and the number of the atoms.
In the image;
There is one sulphur (S) atom, 4 oxygen(O) atoms and 2 hydrogen (H) atoms
Heat from the sun hits the ground and is absorbed. The higher you go, it gets more colder due to the fact that the air doesn't hold onto the radiation as it goes straight through the ground, which is why the top of mountains are very cold, and people are able to die in minutes.