2. we assumed that the gas that is inside the balloon was pure oxygen. in reality, there is a very small amount of another gas inside the balloon. what is that other gas? exclude the possibility of air, even though there was probably a very small amount of air inside the balloon when it was fitted to the flask at the beginning of the experiment.

No because it not possibly

First up write the aim
then write the materials reqd.
then the procedure which you follow
then observation
then conclusion
then you can write lab safety rules or precautions(you can avoid if u want).
lemme' give an example
aim: to observe the double displacement reaction
materials reqd: bacl2 and na2so4, test tubes and a dropper
procedure:
1. take bacl2 in a test tube and na2so4 in the other.
2. then pour bacl2 into na2so4 solution.
3. observe
observation:
you will see that a white precipitate is formed called baso4. along with that common salt or nacl is formed.
the equation is
bacl2+na2so4=baso4+2nacl
conclusion:
a double displacement reaction is observed.
hope it

Ithink the correct answer is 3