7. In the container, there was a higher concentration of oxygen, meaning that the steal wool had more of its surface area exposed to oxygen as opposed to open air where the oxygen molecules reacting with the steel wool are fewer.
8. He would not have observed the same results. The sample in open air would have burned faster than the block of steel in the oxygen container. This is because a block of steel has a lower surface area for reaction than steel wool.
9. Without heating, the reaction would have been slower. This is because heating increases the energy level of the steel and oxygen atoms, making them react faster.