Ph and Buffers Lab

1819 Words Oct 7th, 2010 8 Pages
Buffers, and pH, and Diffusion oh my
The pH of a solution is the measure of the concentration of charged Hydrogen ions in that given solution. A solution with a pH lower than seven is considered to be acidic. A solution with a higher pH is a base. It is very important for organisms to maintain a stable pH. Biological molecules such as proteins function only at a certain pH level and any changes in pH can result in them not functioning properly. To maintain these constant pH levels, buffer solutions are used. A buffer solution can resist change to small additions of acids or base’s. A good buffer will have components that act like a base, and components that act like an acid.
Diffusion is random movement of molecules or other particles
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The next experiment was to test diffusion in agar solution. A petri dish with a layer of solidified agar had four holes punched in it using a No. 5 cork borer. Three holes were punched in a triangle shape with the fourth hole directly in the middle. There should be 15 mm between each outside hole and the middle hole. The three outside holes were filled with one drop each of potassium bromide, potassium Terri cyanide, and sodium chloride. The middle hole was filled with a drop of silver nitrate. It is very important to make sure that none of the holes overflow. After each has been filled allow to sit for an hour and observe the results.
In the final experiment we filled a dialysis bag with starch solution and tied off both ends of the bag so that it is water tight. We then filled a separate bag with sodium chloride and submerge both dialysis bags in two beakers of distilled water. We allowed the bags to sit in the water for 10 minutes. We then put silver nitrate into the water that held the dialysis bag filled with sodium chloride and recorded any changes in the water. We then added iodine to the water that held the dialysis bag of starch and observed any changes in the water.

Table I. pH values of beverages and medicines
Beverages pH Medicines pH
White Grape Juice 3.13 Milk of Magnesia (Mg(OH2) ) 8.2
7- Up 3.31 Sodium bicarbonate (NaHCO3) 8.29
White Wine 3.4 Maalox 8.15
Seltzer Water 4.09

As my hypothesis…