4fe+3o2

i really have no idea how to do this..

Agas has a volume of 0.7 l at 300 mmhg. what would be the new volume at 900 mmhg

Can someone me with 3 and 4 plz. this is for masteries test.

What is the correct name for the compound cocl3? a) cobalt(i) chloride b) cobalt(i) chlorate c) cobalt(ii) chlorate d) cobalt(iii) chloride