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.
When one substance is brought together or mixed with another and the resulting interaction evolves or generates heat, the process is referred to as an exothermic reaction. An exothermic (exo- is a prefix meaning out of) reaction is one where the energy flows out of the system into the environment.