Answer:
I am a room that has a roof but no walls. What am I?
lighter than feather and softer than silk yet the strongest man in the world cannot hold me for more than a few minutes.
I am sometimes referred to as chips
Can not be bought, Can not be sold, Even if it's made of gold. What is it?
I stand in one place yet fill the whole room. I can be filled with molten rock and come in every hue. What am I?
No matter how little or how much you use me, you change me every month.