1. HYDROGEN

2. CHARACTERISTICS.  It´s the first element of periodic table.  It´s symbolized with the letter H.  It was discovered by Henry Cavendish in London, in 1766.

3. WE FIND HYDROGEN.  It´s distributed throughout the universe.  It´s the most abundant element.  It´s part of the 75% of mass, and 90% of the molecules of the universe.  We can find it as gas, in the molecule of water, petroleum, natural gas, and the main constituent of the organic matter.

4. PHYSICAL, CHEMICAL AND BIOLOGICAL CHARACTERISTICS  It´s a colorless, odorless, and tasteless gas.  It´s slightly soluble in water.  It´s an inert gas, but if get as monoatomic is very reactive with other elementes.  One of the element that it reacts is with oxygen producing an explosion  It´s the most flammable substance known.  It´s principal in all organic molecules.

5. IMPORTANCE FOR LIFE.  It´s important because it is part of carbohydrates, our main source energy, are part too of the organic matter, it is also part of many important molecular structures.  Inhalation of this gas can cause health problems, such as dizziness, nausea, vomiting, headache, even death.

6. USES.  Food processing.  Synthesis of ammonia, methanol, and hydrochloric acid.  Liquid refrigerant.  Used as fuel, since in reaction with oxygen produces only water, reducing pollution. And has greater power energetic than other fuels.  It´s used to filling hot air balloons and meteorological balloons.

7. OTHER IMPORTANCES.  We can be obtained from the hydrolysis of water.  It´s and carbon together are main constituents of proteins, lipids and carbohydrates, and these are our sources of energy.