CHEM 106.Lab Report 14: Acids, Bases, Salts and Buffers Acids and bases are pHun.

CHEM 106.Lab Report 14: Acids, Bases, Salts and Buffers Acids and bases are pHun. Introduction:   The topic of acids and bases in chemistry is an interesting one to understand as it relates back to our daily lives. In this topic there are various terms that are of importance to learning the processes and underpinnings that make up this topic. These terms can be found below in the fundamental theories or laws section. In general acids can be identified by their sour taste and they can be found in food items, fruits as well as in the human body, specifically in the stomach. While on the other hand bases, which can be identified by their bitter taste can be found in house hold substances such as in soaps or detergents. In this experiment that is divided into two parts, the first part being titled “ indicator solutions and their colors”, we are given 8 solutions with equal amounts of Molarity being (0.1M) and 6 acid-base indicators. We are to place 4 of the 8 solutions on a wells plate, which its dimensions are (4x6), with the each solution in its given column in correspondence to the wells plate. We are to then place a drop of each of the provided indicators and note/record the change in color that occurs to the specific solution being observed. This procedure is performed twice as the wells plate can only hold 4 solutions at a time. Furthermore we are to then draw conclusions and perform calculations in regards to table 2 which prompts us to find data such as (Calculated pH, ka , kb , specifying if the solution is acid or base, it’s relative strength , and etc.).As for part 2 of this experiment titled “ Buffer Systems and Their pH “ the purpose of this experimental procedure is to create an acetate buffer solution and perform various titrations with the created acetate buffer solution by utilizing a burette apparatus (2 of them). Furthermore we are to then take note of the pH of the buffer system initially and after with the use of pH paper while performing individual titrations with 0.10 M HCl, 0.10 M NaOH , which are to be placed individually in a designated burette. The titrations are to be performed on the acetate buffer solution and as well as on Tap water, noting the pH change with each trial through the use of the pH paper provided. Tabulating all data from both parts on to a graph. Fundamental theories or laws: Acid: an acid is a substance that yields H+ ions when dissolved in water(Arrhenius definition) HA → H ++ABase: is a substance that yields OHions when dissolved in water (Arrhenius Defintion) BOH → B ++OHSalt: results when an acid reacts with a base in a neutralization reaction. The H+ from the acid and the OHions form the base will combine to form water. The remaining ions from the acid and base form the salt. Acid + Base → Salt + Water CHEM 106.Lab 14: Acids, Bases, Salts and Buffers Acids and bases are pHun. Buffer: is a solution of a weak acid and it’s conjugate weak base. They can resist any changes to its pH when small quantities of a base or acid are added.                Materials:      Well plate (4x6)  8 solutions (each 0.1M): FeSO4, NH4Cl,Na2HPO4,NaH2PO4,Na3PO4,NaCl,NaF,Na2CO3  6 indicators: Thymol blue, Methyl orange, Methyl red, Bromothymol, Phenolphthalein, Alizarin Yellow  Lab manual  Calculator  0.10 M Acetic acid solution (25.0 mL)  0.10 M Sodium acetate solution ( 25.0 mL)  pH paper( ranging from 0-14)  0.10 M Hydrochloric acid (HCl)  0.10M Sodium Hydroxide (NaOH)  2 Burette Apparatus  Tap Water(25.0 mL)  150 mL beaker  2 100 mL beaker  Deionized water    Observations and experimental:      Part 1: Indicator solutions and Their Colors Table 1: 0.1 M solution of Thymol blue Methyl orange Methyl red Bromothymo l blue Phenolphthalei n Alizarin Yellow FeSO4 Red Dark orange Pink Light yellow White Cloudy Clear brown NH4Cl Yellow Light orange Clear pink Light green Clear White Light yellow Na2HPO4 Dark blue Light Orange Light yellow Blue Pink Light yellow NaH2PO4 Dark yellow Light orange Pink Light yellow Clear white Light Yellow Na3PO4 Dark Blue Light orange Light yellow Blue Pink Reddish Orange NaCl Dark blue Light orange Light yellow Aqua/ Greenish blue Cloudy White Light yellow NaF Dark blue Light orange Light yellow Greenish Blue Cloudy white Light yellow Na2CO3 Dark blue Light orange Light yellow Blue Pink Reddish Orange Table 2 0.1 M solution of Ka Kb Calculate d pH Acid or base Relative strength Approximat e pH based on the indicator FeSO4 1.2 x10- 2 8.33 x 10-13 7.46 Acid Strong 4.0 NH4Cl 5.55 x 10-10 1.8 x 10-5 5.13 Acid Weak 4.5 Na2HPO4 7.5 x 10-3 1.34 x 10-12 7.56 Base Weak 8.0 NaH2PO4 6.23 x 10-8 1.61 x 10-7 4.10 Acid Weak 5.0 Na3PO4 4.8 x 10-13 2.1 x 10-2 12.66 Base Strong 14.0 NaCl 1 x 10-7 1 x 10-7 7 Acid Weak 5.0 NaF 7.2 x 10-4 1.4 x 10-11 8.07 Acid Weak 5.0 Na2CO3 4.8 x 10-11 2.1 x 10-4 11.66 Base Strong 12.0 Calculations for Part 1: Table 2(using appendix in lab manual and online table that had the same soltuion ) 0.1 M FeSO4 Ka = 1.2 x 10-2 Kb = Kw/Ka = 1 x 10-14/1.2 x 10-2 = 8.33 x 10-13 SO42- + H2O <==> HSO4 - + OH8.33 x 10-13 = x2 /0.1 x = [OH- ] = 2.88 x 10-7 M