As you can see from the title, I'm puzzled as to what occupies the spaces in between the particles in a gas. Take air for example. In Chemistry, I have learnt that the particles in a gas are far apart. Hence the particles in the air around me are far apart. But if there are no particles in the spaces,it means no matter exists. So is it a vacuum? If so, why don't I experience it on a daily basis? Sorry if the question is trivial, but it has been bugging me for some time.