The experiment allowed students to explore different electrolytes and classify them into acids, bases and salts by using different indicators or by measuring the pH levels of each. The experiment also helped students classify different substances through their conductivity properties. The preparation of a 1 M stock solution from NaOH pellets diluted to a 0. 1 M NaOH solution was also utilized in making the students understand the concept of titration. Using 0. M NaOH as a standard solution, the concentration of an unknown acid was calculated from the endpoint of an acid-base titration. II. Keywords: acid, base, salt, pH, electrolytes, conductivity, titration III. Introduction The experiment made the students classify substances as acids, bases, and salts using different indicators; identify pH; classify electrolytes as weak or strong based on conductivity; prepare 1 M NaOH from NaOH pellets; prepare 0. 1 M NaOH from 1 M NaOH; determine endpoint of an acid-base titration; and calculate the concentration of an unknown acid solution based from titration data.
Electrolytes are substances that dissociate into ions when dissolved in water. They are classifiable into acids, bases and salts using different indicators. An acid releases hydrogen ions, donates protons and accepts electron pairs. It is usually sour in taste and reacts vigorously with most metals. It also changes blue litmus paper to red. Moreover, it has a pH less than 7 and can be used to neutralize bases. A base, on the other hand, releases hydroxyl ions, accepts protons and donates electron pairs. It usually has a bitter taste and is nonreactive to metals.
The Term Paper on Determination Of An Unknown Amino Acid From Titration
Determination of An Unknown Amino Acid From TitrationAbstractExperiment 11 used a titration curve to determine the identity of an unknown amino acid. The initial pH of the solution was 1. 96, and the p Ka " sound experimentally were 2. 0, 4. 0, and 9. 85. The accepted p Ka values we refound to be 2. 10, 4. 07, and 9. 47. The molecular weight was calculated to be 176. 3 while the accepted value was ...
It has a pH more than 7 and changes red litmus paper to blue and can be used to neutralize acids. Salts result from the neutralization of an acid with a base. There are different indicators used to classify electrolytes. Litmus paper, most of which, turns from blue to red with acids and red to blue with bases. Phenolphthalein changes from colourless to pink at a pH range of 8. 0 to 9. 8. An acid gives a clear color with phenolphthalein while a base gives a reddish violet to pink color. Congo red changes from blue to red at a pH range of 3. 0 to 5. 0. With Congo red, acids give a blue color while bases give red.
The pH paper gives the exact pH of a substance through the different colors of its layers. The pH scale is logarithmic and as a result, a whole pH value below 7 is 10 times more acidic than the next higher value. Conductivity determines the extent of dissociation of a solute therefore classifying them as strong or weak electrolytes and non-electrolytes. Electrolytes conduct electricity while non-electrolytes do not, since they do not dissociate into ions when in a solution. A preparation of a diluted solution involves adding more solvent to a solution. In this experiment, dilute solutions are prepared from a stock solution.
Titration was used to determine the concentration of an unknown acid. In the process, small amounts of the standard solution are added until the endpoint is reached. This is determined by the change in color of the indicator used. From the volumes of the unknown acid and the standard solution, the molarity (M) was calculated. IV. Experimental In this experiment, different electrolytes are classified into acids, bases and salts. 5 drops of 0. 1 M solutions of NaOH, NH4Cl, HCl, HC2H3O2, NaCl, C12H22O11 and distilled water were tested with litmus paper, phenolphthalein and congo red to classify them.
The Term Paper on Aqueous Solution Acid Base Conjugate
CHEMISTRY 122 CHAPTER 17 NOTES CHAPTER 17 EXERCISES (THESE ARE NOT TO BE TURNED IN, BUT QUIZ QUESTIONS WILL BE TAKEN FROM THESE EXERCISES SO IT IS TO YOUR BENEFIT TO DO THEM): 2, 3, 5, 6, 8, 10, 13, 15, 16, 18, 19, 21, 23, 25, 27, 28, 29, 31, 33, 37, 39, 41, 43, 44, 47, 48, 50, 53, 57, 60, 63, 64, 67, 70, 71, 73, 75, 78, 80, 87, 95, 102, 112 Chemistry of Acids and BasesSvante Arrhenius (1884) ...
Colors of each were noted. The pH of the solutions were also taken using pH paper. Afterwards, 1 mL of 1 M HCl and 1 M NaOH were mixed in a test tube. This mixture was tested with available indicators. The procedure was repeated using 1 M acetic acid in place of HCl. The conductivity test was performed to determine whether the solutions had good, weak or no conductivity. Before doing the titration process, a stock solution of 1 M NaOH was prepared using NaOH pellets. The weight of NaOH pellets needed to make 100. 00 mL of 1 M NaOH was calculated.
This amount of pellets was weighed in a watch glass, then dissolved in 50 mL water. The solution was transferred to a 100 mL volumetric flask and diluted to the mark with distilled water. A 0. 1 M of NaOH was prepared from the available concentration. Using M1V1 = M2V2, the volume of NaOH from available concentration needed to prepare 100 mL of 0. 1 M NaOH was calculated. The measured volume was diluted to 100. 00 mL with distilled water in a volumetric flask. In the titration proper, a base buret was washed thoroughly with soap and water. It was then rinsed thrice with 3 mL portions of the standard base.
