Nutrition and Growth of Bacteria (page 4) (This chapter has 6 pages) Â© Kenneth Todar, PhD Physical and Environmental Requirements for Microbial Growth The procaryotes exist in nature under an enormous range of physical conditions such as O2 concentration, Hydrogen ion concentration (pH) and temperature.
In a double replacement reaction parts of two compounds switch places to form two new compounds. Two reactants yield two products. For example when silver nitrate combines with sodium chloride, two new compounds--silver chloride and sodium nitrate are formed because the sodium and silver switched places.
The types of chemical changes that are discussed here include combination and decomposition. Combination happens when two or more substances combine together in a chemical reaction to form one or more different substances. Combination reactions can result in the corrosion of metals like iron with oxygen from the air. Combustion reactions, such as a burning candle, are also examples of the chemical change through the combination of wax and oxygen in a reaction that produces heat, light, carbon dioxide and water.