I need to classify each by either as a element, compound, homogeneous mixture or heterogeneous mixture. So far I have the following:
1. rust [iron(III) oxide]) - ?
2. diamond - ?
3. carbon dixoide - compound
4. air in a sealed flask - ?
5. vinegar and oil - ? heterogeneous mixture
6. water (pure) - compound
7. 14 carat gold - homogeneous mixture
8. unsaturated aqueous sodium choloride - ?
I am not sure of the ones with the ? could you give some help with explaination I would greatly appreciate it.