Acids, Bases, and Buffers
The pH scale is used to determine how acidic or basic a solution is, ranging from 1-14. The most acidic of all acids are at a pH level of 1 and the most basic of all bases are at 14. The neutral pH level is 7, which is what drinking water is. The pH level is determined by the amount of H+ ions present in a solution, and the more H+ ions there are the more acidic it is, and the lack of these ions results in more basic solutions. One distinguishing feature between acids and bases is that acids contain H+ ion and bases contain OH- ions. The reason why water is a neutral substance is because it has the same number of H+ (Hydrogen) ions as OH- (Hydroxide) ions. H20⇔ H+ + OH-
A buffer is a solution that only changes pH level slightly when added a strong acid or base to it. When an acid is added to a neutral substance, the pH level increases noticeably. When an acid is added to a buffer there is a small change in pH level, and this is because a buffer is a mixture made of a weak acid and a weak base. The weak acid/base mixture allows for either an acid or a base to be added to it without a dramatic change in pH level. Buffers are very important because they help to keep pH levels constant in fluids like blood, which can’t have a pH level above or below 7.3-7.5 or else it is dangerous. The most important buffer found in biological process is bicarbonate. Bicarbonate is important because it can accept Hydrogen ions and also donate them, which means it can react with either an acid or a base with only a slight change in pH level. H2O + CO2 ⇔ H2CO3 ⇔ H+ + HCO3-
The objective of the experiment is to determine what solutions act as buffers. This is tested by adding small increasing amounts of acids and bases to various materials to record the change in pH level. The hypothesis being tested is that the solutions that increased the most don’t act well as buffers, and the solutions that changed the least are the better buffers....
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