PS-3.2    Infer the practical applications of organic and inorganic substances on the basis of their chemical and physical properties              
Key Concepts
Organic substances: hydrocarbon, protein, carbohydrate, lipid
Inorganic substances
    The physical and chemical properties of a substance determine how a substance is used. For instance Neoprene, a man made polymer, is made of long complex molecules that lie side by side. This structure makes the Neoprene very flexible, elastic, and strong enough to resist abrasion. Neoprene can stretch and return to its original shape and size. These properties make neoprene the substance of choice for making automobile tires. Go to this link and read what an industry leader has to say about the properties of Neoprene and how these properties determine its many uses.
  Neoprene is an example of an organic compound. It is considered to be organic because it contains Carbon and Hydrogen atoms bonded chemically to each other.  Inorganic substance do not contain these Carbon=Hydrogen bonds. Inorganic compounds are often salts that consist of chemical combinations of metals and non-metals.
Polymers are large molecules that are made up of smaller molecules, called monomers. Proteins are organic polymers that are made by linking together smaller amino acid molecules into longer chains. Protein molecules of various configurations can function in a variety of different ways. Some protein molecules act as catalysts that help chemical reactions take place without undergoing permanent changes themselves. Enzymes are organic catalysts that help chemical reactions take place in living organisms. Salivary amylase is an enzyme in saliva that helps break complex sugars and starches down into simpler sugars. In the process, the salivary amylase molecules “unlock” the larger sugar and starch molecules, breaking them down into simple sugars like glucose. Some protein molecules act as inhibitors that slow down or stop chemical reactions in living organisms. These molecules are responsible for allowing complex chemical reactions to proceed in small steps, rather than all at once. A good example of this is the process of respiration. I the process of respiration enzymes control the oxidation of glucose. In a series of steps, called the Krebs cycle, enzymes control the oxidation of glucose (sugar) thus releasing energy for the body to use. Proteins also serve living organisms in the process of tissue building.
The following summary of organic molecules is taken directly from the South Carolina Physical Science Standards.
·        Protein molecules are long chains of small units (amino acid monomers) that are arranged in various configurations so they can form a wide variety of molecules.  Proteins serve many functions in living organisms such as catalysts (enzymes) and tissue building.
·        Carbohydrate molecules (sugars and starches), provide organisms with energy when they break down into smaller molecules.
·        Lipid molecules (fats and oils) are well suited for long term energy storage because lipids are harder to break into smaller particles than carbohydrates and therefore provide more energy.
    Hydrocarbons are organic molecules that contain various combinations of the elements carbon and hydrogen. Because hydrocarbons contain many carbon atoms they are commonly used as fuels. Fossil fuels such as gasoline, kerosene, jet fuel, diesel oil, and methane gas, undergo the process of combustion in the presence of oxygen to produce carbon dioxide and water vapor. During the process of combustion, the energy that was held in the chemical bonds between the carbon and hydrogen atoms is released as heat and light.
   Many hydrocarbons can form long chain polymer molecules. Plastics and other synthetic fibers such as Nylon® and Neoprene® are manufactured products that are made from hydrocarbons.                  
    The properties of an inorganic substances also determines its suitability for any given use. Lead was used by the Romans more than 2000years ago to make pipes to carry water. They used lead because it has the properties of malleability and ductility. Materials that are malleable can be flattened out into sheets. Substances that are ductile can be drawn out into wires and formed into various shapes without breaking or heating. The Romans hammered lead into sheets and then wrapped the sheets around smooth wood logs. When the logs were pulled out the result was a lead pipe, perfect for carrying water or sewage.
   One of the first metals used by the ancients was copper. Copper can be found in its natural form in nature. It is malleable and ductile. Because of these properties, it can be easily shaped into tools and weapons. Today, people use copper for electrical wires because it is an excellent conductor of electricity. We also use Aluminum for aircraft and light weight automobile parts, because it has a low density, making it light and strong.