. Fuel cells convert chemical energy in the form of oxygen and
hydrogen into an electric current, with water as the by-product (Fuel). Fuel cells are being developed for use in cars because they are more economical than gasoline engines and cause less pollution: the only exhaust from a hydrogen fuel cells is water vapor. The advantages of fuel cells are that they do not produce greenhouse gases. Fuel cells do not make much noise, and are cheap to maintain and operate as they have no moving parts. They are very efficient electric producers. The disadvantages of fuel cells are that they currently have a high initial investment cost, and refueling is a problem because there is no supporting infrastructure as yet the way there is for gasoline engines (gas stations). Fuel cells can reduce the pollution problem and so be beneficial for the environment, and reduce the dependence on oil, supplies of which will not last indefinitely.
4. Ozone depletion is caused primarily by manmade compounds
known as chlorofluorocarbons (CFCs), which contain chlorine and bromine (Causes). These chemicals get into the atmosphere and are not washed back to earth by rain, and do not react with other chemicals. They are broken down by UV light in the stratosphere, releasing free chlorine, which is involved in the destruction of ozone and its conversion to oxygen, freeing the chlorine to react again. Ozone protects the earth from UV-B radiation, which is harmful to the skin, eyes and immune system of humans and animals (CIESIN). It is also deleterious to phytoplankton which is at the bottom of the food chain and so could affect all the levels above it (CIESIN/Environmental).
5. The 2001 Nobel prize winners in chemistry were two
Americans, William Knowles and K. Barry Sharpless, and a Japanese Ryoji Noyori, who worked on projects which improved the control of chemical reactions (Drugs). Their work helped in the development of heart drugs ...