As a model of the new system a prototype allows for several forms of communication. First, it allows the developers to communicate to the users their understanding of the requirements. (Obviously before a prototype can be built there must be some initial requirements discussions between developers and users).
(Arrhenius) a substance that yeilds hydroxide ions in an aqueous solution; metallic oxides in water. Buffers. substances that in solution are capable of neutralizing, within limits both acids and bases, and thereby maintaining the original or constant pH of the solution; substances that prevent changes in pH. Ex. borax, sodium phosphates, and citrates. Crystallization. the process by which a substance is given definite form.
There is a scale for acids and bases just like everything else. Here are a couple of definitions you should know: Acid: A solution that has an excess of H + ions. It comes from the Latin word acidus, which means sharp or sour. Base: A solution that has an excess of OH-ions. Another word for base is alkali. Aqueous: A solution that is mainly water. Think about the word aquarium. AQUA means water. Strong Acid: An acid that has a very low pH (0-4). Strong Base: A base that has a very high pH (10-14). Weak Acid: An acid that only partially ionizes in an aqueous solution. This means that not every molecule breaks apart. Weak acids usually have a pH close to 7 (3-6). Weak Base: A base that only partially ionizes in an aqueous solution. This means that not every molecule breaks apart.