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Determination of the concentration of acid in gastric juice

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Determination of the concentration of acid in gastric juice Introduction In this experiment in will be using a standard solution of hydrochloric acid to determine the morality of a solution of sodium hydroxide. You will then use this standardized solution of sodium hydroxide to determine the concentration of acid in the sample of gastric juice. Then I will use my results to calculate the pH of the sample and compare the calculated value to the pH determined using a pH meter Background information Molarity The concentration of a substance in solution is the number of moles of those substance moles per unit volume of solution. In particular, the morality of a substance in solution is the number of moles per liter of solution: The stomach and Gastric juice The stomach is composed of five layers which are the innermost layer is called the mucosa. Stomach acid and digestive juices are made in the mucosa layer. The next layer is called the sub mucosa. The sub mucosa is surrounded by the muscularis, a layer of muscle that moves and mixes the stomach contents. The next two layers, the subserosa and the serosa are the wrapping for the stomach. The serosa is the outermost layer of the stomach. Gastric juice is a strongly acidic which as a pH varying from 1 to 3 its essential constituents are the digestive enzymes pepsin and rennin hydrochloric acid, and mucus. ...read more.


Once in dilute solution the hazard from the dye is considerably reduced and the solvent perhaps Presents the greater hazard. Many dyes are described as 'CANCER SUSPECT AGENT' If swallowed Wash out the mouth and give a glass or two of water. Seek medical attention as soon as possible. If solid or solution gets in eyes Flood the eye with gently running tap water for 10 minutes. Seek medical attention. If spilt on skin or clothes Remove contaminated clothing. Flood the area with water and wash thoroughly with soap and Cold water. Method * Add 25cm3 of hydrochloric acid in to a conical flask using a pipette. * Fill the burette to the with sodium hydroxide Take the initial readings of the burette and record them on to a table. * Add 1 to 2 drops of phenolphthalein indicator in to the conical flask * Titrate the hydrochloric acid in the conical flask against the sodium hydroxide solution from the burette. * While titrating use the white tile, place it underneath the conical flask, so it helps you to see the end point. The end point is when the colour of the solution turns pink. Aim to get a slight touch of pink, and not a dark colour. * Take reading off the burette once you have got the end point, and try to read it to the nearest 0.01cm3 record the reading on to a table. ...read more.


I believe that I completed successfully. having completed aims with results which was Average Volume of sodium hydroxide solution used - 31.3cm3 (31 + 31.6 + 31.4 / 3 = 31.3) Number of moles of NaOH present in this volume - 2.5 x 10-4 (25cm3 / 1000 x 0.01 = 2.5 x 10-4) Therefore: Molar concentration of NaOH - 7.9872 x 10-6 (2.5 x 10-4 / 31.3 = 7.9872 x 10-6) Aim 2 To determine the number of moles of sodium hydroxide present in gastric. Once again I completed successfully. having completed aims with results which was Average volume of sodium hydroxide solution used - 40.5 cm3 (40.6 + 40.7 + 40.3 = 40.5) Number of moles of NaOH present in this volume - 6.2 x 10-6 moles (2.5 x 10-4 / 40.5 = 6.2 x 10-6) Therefore number of moles of HCL in 25cm3 of gastric juice - 6.2 x 10-6 moles Therefore molar concentration of HCL in gastric juice - 0.01 mol dm-3 (1000/25 x 2.5 x 10-4 = 0.01) Concentration of hydrogen ions in gastric juice - 0.01 mol dm-3 Overall I believe this experiment went very well and I have lean a lot in being accrued and precise and next time round when I am doing this experiment I should be even better at it. ?? ?? ?? ?? Rakib Ahmad Forensic Science 17/10/06 1 ...read more.

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