A picture to show simply how the atoms may fill space. The white is hydrogen and the red is oxygen.
Hydrogen peroxide is a chemical compound. Its molecular formula is H2O2. It is used as a cleaner, and as hair bleach. In a concentration of 3% (meaning that there are 3 grams of hydrogen peroxide for 100 grams of a water solution), it can be used to treat wounds. Over time it will slowly become oxygen gas and water through decomposition.