Introduction
Buffer is a solution that resists a change in pH when bases or acid are added. Solutions that are acidic contain high concentrations of hydrogen ions (H+) and have pH values less than seven. Buffer usually consist of a weak acid, and its conjugate base or a weak base and its conjugate acid. The function of buffer is to resist the changes in hydrogen ion concentration as a result of internal and environmental factor. This buffer experiment is important so that we relies the important of buffer in our life. Besides that, it is also important so that we master the buffer preparation techniques and can conduct the experiment ourselves without anyone to instruct us. Other than that, we got to learn how to operate a pH meter and we
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The NaH2PO4 and Na2HPO4 powdered were weighted by using weighing machine, followed the mass that has been calculated in step (3). The NaH2PO4 and Na2HPO4 powdered were mix in a 500 mL beaker. 500 mL of distilled water were measured by using a 500 mL measuring cylinder, then is poured inside the 500 mL beaker containing both the powdered. The mixture were stirred by using a glass rod until the mixture is fully dissolved. The solution were tested by using calibrated pH meter to get the pH value of the solution.
Results and Discussions pH ratio between acid and base:
7.3 = 6.82 + x x = 0.48
0.48 = log ([base])/([acid])
100.48 =base/acid salt/acid = 3.02
There, 1 acid : 3 base
calculate number of mole of acid and base to find the mass :
molar = mol/L
50 mM = (mol )/(0.5 L)
mol = 25 mol
number of mole of NaH2PO4
25/4 = acid = 6.25 mol number of mole of Na2HPO4
25/4 × 3 = salt = 18.75 mol
to calculate the mass of the acid and base :
Mass of NaH2PO4
(6.25 mol)/(119.98 g/mol)=0.052g Mass of Na2HPO4
(18.75 mol)/(141.96
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A good buffer should have some of the characteristic such as have a pKa between 6 and 8. This is because most of the biochemical experiments have an optimal range of 6-8. Besides that, the bufferl used should be soluble in water. This is because the reaction only will take part in aqueous environments. Lastly, the salt used in this experiment should have the minimal effects in the experiment. Thus, the buffer components should not affect the ions involved in the biochemical reactions being