Sure, I'd be happy to help with that question.
1. Gases exert pressure. (✔)
2. Gas is a state of matter that has no fixed shape and no fixed volume. (✔)
3. Smoke and hot gases tend to go downwards. (*)
4. Gases expand when heated and contract when cooled. (✔)
5. The densities of gases are relatively high compared to the densities of solids and liquids. (*)
6. The force of intermolecular attraction between gas particles is negligible. (✔)
7. There is no limit to the amount of air that can be pumped into a bicycle tire. (✔)
8. Gases mix evenly and completely when contained in the same vessel. (✔)
9. Gases are difficult to compress when pressure is applied. (*)
10. Cold air tends to go upwards. (*)
I hope this helps clarify the correctness of each statement for you!