Hydrogen Peroxide in Space

Molecules of hydrogen peroxide, H₂O₂, have been found for the first time in interstellar space by astronomers using the European Southern Observatory-operated APEX telescope in Chile.
The hydrogen peroxide has been detected in a region of our galaxy about 400 light-years away where it is very cold (around -250^oC) and contains dense clouds of cosmic gas and dust in which new stars are being born. The clouds are mostly made of hydrogen, but contain traces of other chemicals, and are prime targets for astronomers hunting for molecules in space. The amount of hydrogen peroxide in the cloud is just one molecule for every ten billion hydrogen molecules.

Hydrogen peroxide is a key molecule for both astronomers and chemists. Its formation is closely linked to two other familiar molecules, oxygen and water, which are critical for life. Because much of the water on our planet is thought to have originally formed in space, scientists are keen to understand how it is created. Hydrogen peroxide is thought to form in space on the surfaces of cosmic dust grains, very fine particles similar to sand and soot, when hydrogen (H) is added to oxygen molecules (O₂). A further reaction of the hydrogen peroxide with more hydrogen is one way to produce water (H₂O).

Reference
P. Bergman, B. Parise, R. Liseau, B. Larsson, H. Olofsson, K. M. Menten, R. Güsten. Detection of interstellar hydrogen peroxide. Astronomy & Astrophysics, 2011; 531: L8 DOI: 10.1051/0004-6361/201117170

Further Reading
Lewis Structures (electron dot diagrams)
Intramolecular Forces
Intermolecular Forces
Temperature Conversions
Ideal Gas Calculations


Study Questions

1. Draw a Lewis Structure (electron dot diagram) for hydrogen peroxide.
2. Describe the nature of bonding that occurs within the hydrogen peroxide molecule.
3. The melting point of pure hydrogen peroxide is -0.43^oC . Explain why the melting point of pure hydrogen peroxide is slightly less than the melting point of pure water.
4. The boiling point of pure hydrogen disulfide, H₂S₂, is 70.7^oC while the boiling point of hydrogen peroxide is 150.2^oC. Explain why the boiling point of hydrogen peroxide is more than twice the boiling point of hydrogen disulfide.
5. Convert the following temperatures in ^oC to temperatures in Kelvin:
   • -250 ^oC
   • -0.43 ^oC
   • 70.1 ^oC
   • 100 ^oC
   • 150.2 ^oC
6. The amount of hydrogen peroxide in the cloud is just one molecule for every ten billion hydrogen molecules. Convert this to:
   • a concentration of hydrogen peroxide in parts per million.
   • a concentration of hydrogen peroxide in grams of hydrogen peroxide per kilogram of hydrogen
7. In outer space, 'atmospheric' pressure is about 100μPa Convert this to a pressure in:
   • kPa
   • atm
   • mmHg
   • Torr
8. Calculate the temperature of outer space if the atmospheric pressure of 100μPa is caused by the presence of 10 hydrogen molecules per cubic metre of space.