Buffer Solutions
Preparation and testing the properties of buffer solutions
1. To prepare two buffer solutions of pH values of 5.2 and 8.8
2. To check the pH and buffer action of the prepared buffers
3. To examine the effect of dilution of the prepared buffers on their
pH and buffering capacity
Introduction
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A buffer is a physical area or object protecting something. A chemical
"buffer" is a mixture of two compounds that protects the pH of a
solution from undergoing large changes when small amounts of acid (in
the form of hydroxonium ion [H3O+]) or base (in the form of hydroxide
ion [OH-]) are added. Buffers usually contain a weak acid and its
conjugate base or a weak base and its conjugate acid. One of the two
compounds in a buffering system acts as a proton donor, releasing H+
when pH rises, and the other as a proton acceptor, taking up H+ when
pH drops.
[IMAGE]
Applications of buffer in chemistry include manufacture of dyes,
photographic materials, leather etc. In biochemistry the buffering
action of blood is given by the bicarbonate system, which keep the
blood pH near 7.4.
H2CO3 [IMAGE]HCO3- + H+ H2O + CO2 [IMAGE]H2CO3
[IMAGE][IMAGE][IMAGE] A number of cytoplasmic proteins can act as
buffers as they contain both acidic and basic groups. NH2- -COO- NH3+-
-COO- NH3+- -COOH
Overall negatively changed overall neutral overall positively charged
They can take up H+ the medium is acidic, and OH- when the medium is
alkaline.
In this experiment, CH3COOH(aq) and CH3COONa(aq) will make the acidic
buffer with pH<7. NH3(aq) and NH4Cl(aq) will make the alkaline buffer
with pH>7. A small amount of HCl(aq) and NaOH(aq) are added to the
buffer to observe the change in pH. The buffering capacity VS change
in concentration of buffer and buffering action of diluted buffer is
investigated.
Buffer action is the actual reaction by which a buffer system
maintains the pH upon addition of acid/base.
The capacity of the buffer is determined by the amounts of salt and
More hydrogen ions in a solution is a result of lower pH, while fewer hydrogen ions in a solution is a result of increased pH. Meaning that a lower pH level results in a higher enzyme activity reaction and a higher pH level results in a lower enzyme activity reaction (Christianson, 2011 ).
CL-, as the ions of H+ and OH- react to form H2O. These spectator ions
Homeostasis is the internal chemical balance that occurs in all living things. The concentration of hydrogen ions and hydroxide ion creates acids and bases. They are measured using the pH scale, which runs from 0 to 14. In the scale 7 is neutral. To be considered an acid, the concentration of the ion must be between 0 and 6, To be considered a base, the concentration of the ion must be between 8 and 14. Most living things have a concentration range from 5.6 to 8.5. There are many exceptions to this rule, such as the pH
The alternate hypothesis is that there exists an optimal pH level for catecholase enzyme in which the catecholase enzyme can operate with the highest possible
The effect of a change in PH on enzymes is the alteration in the ionic
An acid becomes a solution, when a hydrogen ion is released. A base becomes a solution, when a hydroxide ion is released. There are three classes of acids and bases. An acid produces H+ in a solution and a base produces OH. This is a theory called the Arrhenius definition. A man by the name of Svante Arrhenius developed this theory. Acids and bases can be defined their physical and chemical observations.
Abstract: Enzymes are catalysts therefore we can state that they work to start a reaction or speed it up. The chemical transformed due to the enzyme (catalase) is known as the substrate. In this lab the chemical used was hydrogen peroxide because it can be broken down by catalase. The substrate in this lab would be hydrogen peroxide and the enzymes used will be catalase which is found in both potatoes and liver. This substrate will fill the active sites on the enzyme and the reaction will vary based on the concentration of both and the different factors in the experiment. Students placed either liver or potatoes in test tubes with the substrate and observed them at different temperatures as well as with different concentrations of the substrate. Upon reviewing observations, it can be concluded that liver contains the greater amount of catalase as its rates of reaction were greater than that of the potato.
From the experimental data, the [H+] decreases as the concentration of the HCl in each solution decreases. Since acids dissociate in water, the dilution of the acid’s concentration (Macid) will determine the number of free hydrogen ions in the solution, being that they are equal to each other when the -log is used. By changing the concentration of the HCl, the acid strength decreases, as shown in the change in pH, due to the presence of H+ ions as they break away from the original molecules of the acid. These free ions are in the form of hydronium ions, which shows in the decrease of the H+ in the table above.
Solubilisation and transport of lipids (in an aqueous environment): acids within the bile are lipid carriers and are able to make lipids more soluble by forming micelles (making a lose structure of particles in this case...
The presence of HpUrel, which is a proton gated inner membrane urea channel, is essential for survival in the acidic mammalian stomach. The pH has a major role in determining whether or not the channel closes or opens. When the pH is neutral, the channel is closed. When the pH is acidic, the channel opens; thus, allowing the access of urea to cytoplasmic urease. The channel fully opens at a pH of about 5.0, which enables the entry of urea into the bacterium. Even in the acidic environment of the stomach, urease buffers the periplasm to a pH of about 6.1, and neutralizes the incoming protons. This is essential for the survival of Helicobacter
Nowadays, a lot of research teams are trying to develop new ways to treat cancer or to improve the efficacy of already existing treatment strategies. To do this, it is important to understand the differences between tumor tissue and healthy tissue. One of these differences concerns the pH in cancerous environment. In normal cells, intracellular pH is generally around 7,2 and thus lower than the extracellular pH of 7,4. Cancer tissue however shows a reversed pH gradient: the intracellular pH is increased (>7,4) and the extracellular pH is lower than usual (6,7-7,1). This gradient is maintained thanks to changes in the expression and activity of some particular plasma membrane ion pumps and transporters that facilitate the H+ efflux. Due to the increased intracellular pH, cell proliferation and the evasion of apoptosis is possible and the metabolic adaption is facilitated. Moreover, for efficient directed cell migration a higher intracellular pH is even obligatory. The decreased extracellular pH also offers some advantages for the development of the tumor : HCO3—-dependent buffering is limited, extracellular matrix remodeling is promoted and acid-activated proteases are stimulated which makes tumor cell invasion and dissemination easier (Webb e.a. 2011).
The body has a buffer system that mixes of a weak acid and a weak base to resist changes in pH, it is the least efficient but it is quick. It includes buffers such as bicarbonate, phosphate, and a few proteins that help too. The respiratory system place a part too, it is a bit slower but it is more effective than the buffer system. The kidney secretion of hydrogen ions, is the most effective but is the slowest. It lowers the pH of the blood and raises pH of the urine.
strong acid or base does not necessarily yield a drastic jump in pH. The acid
acids. I only tried the 1 molar acid, but if I were to repeat the
The highly acidic peptic environment make it almost impossible for any organism to exist, but thanks to the ability of H.Pylori to produce the enzyme Urease, H.Pylori can thrive in the stomach. Urease has the ability raises the surrounding pH throughout converts urea to ammonia plus carbon dioxide, raising the pH of the surrounding area. Which can lead to mild protection against gastric acid.