Lab Report On Redox Titration

1. To prepare a standard solution of oxalic acid and use it to standardize an unknown  sodium hydroxide solution.

Stoichiometry is a very important part of chemistry. Stoichiometry refers to calculating the masses of molecules and their products . The reactants are usually given and stoichiometry is used to find the products of the equations as well balancing the equation. An example of this would be sodium chloride (NaCl). Stoichiometry will say that if there are ten thousand atoms of sodium and one atom of chlorine, only one molecule of sodium chloride can be made and that fact can never be changed.

The purpose of this semester long experiment was to determine an unknown organic acid. An organic acid is an organic compound with acidic properties. A base reacts with acids to form salts. Titrations are used to determine the concentration of unknown substances. The purpose of the KHP experiment was to determine the molarity of NaOH. HCl titrations are mainly to check technique and used to verify the molarity of NaOH solution. The hypothesis is that this acid is C4H3OCOOH.

Table 2: Consists of color extract taken from a red cabbage for a natural indicator. The pH reading that was measured by using the pH meter and the result of the pH reading to determine whether the solution was acidic or basic.

Chemistry 102 is the study of kinetics – equilibrium constant. When it comes to the study of acid-base, equilibrium constant plays an important role that tells how much of the H+ ion will be released into the solution. In this lab, the method of titrimetry was performed to determine the equivalent mass and dissociation constant of an unknown weak monoprotic acid. For a monoprotic acid, it is known that pH = pKa + log (Base/Acid). When a solution has the same amount of conjugate base and bronsted lowry acid, log (Base/Acid) = 0 and pH = pKa. By recording the pH value throughout the titration process and determining the pH at half- equivalence point, the value of Ka can be easily calculated. In this experiment, the standardized NaOH solution has a concentration of 0.09834 M. The satisfactory sample size of known B was 0.2117 g. The average equivalent mass of the unknown sample was found to be 85.01 g, pKa was found to be 4.69, which was also its pH at half-equivalence point and Ka was found to be 2.0439×〖10〗^(-5). The error was 1.255% for equivalent mass and 0.11% for Ka. In other word, the experiment was very precise and accurate; the identity of the unknown sample was determined to be trans-crotonic by the method of titrimetry.

Measure the initial width, length, and thickness of the steel specimen using a Dial Caliper. Relieve pressure in Amatrol T9014 and adjust the height of the bottom platform to insert steel specimen. Insert one pin into the bottom platform to hold the steel specimen into the fixture. Slide two locking bars down the steel specimen. Adhere one locking bar to the bottom of the specimen and one at the top, lock them in place using the attached thumb screws. Insert the Linear Vernier Caliper in the top locking bar and zero out the caliper, allowing it to rest on the bottom locking bar. Compress the hydraulic cylinder until the indicator reads a force of zero. Lock the Linear Vernier Caliper in place by tightening the top thumb screw. [1] Compress

The mixture was then transferred to a clean centrifuge tube via pipet, carefully not wetting the upper walls of the tube. Zinc granules were then added and the tube was immediately plugged with cotton 1/3 of the way into the tube. The tube was then warmed in a hot water bath for about 5 minutes, the folded red litmus paper was inserted at the top of the tube with a wet crease. After a few minutes, nitrate is indicated on the wet crease of the litmus paper, turning it blue. For the Carbonate test, 25 mg of carbonate sample was added to a centrifuge tube and 3 drops of 6 M H2SO4 was added. A disposable pipet was used to transfer a drop of Ba(OH)2, that hung directly from the pipet over the carbonate solution, and the observations of the drop were recorded.

2. (5 pts) List and explain the names and affiliations of the various characters/stakeholders in this story – I’m looking for us to use the story to map out the complexities that are generally associated with solving public health puzzles – the stakeholders you list and explain here should apply to many of the cases we consider going forward.

The Uptake of Neutral red dye by saccharomyces cerevisiae in the presence of a metabolic inhibitor

Within an acid-base titration the titration curve resembles the strengths of the corresponding acids and bases. A strong acid will correspond with a weak conjugate base, and a weak conjugate acid will correspond with a strong base. This is based on the Bronsted-Lowry model. The weak acid will donate protons to the hydroxide ion. Weak acids will have a low Ka value, the Ka value is the tendency of the acid to dissociate:

Procedure B (Establishing a Baseline)- The amount of KMnO4 added to the solution is proportional to the amount of hydrogen peroxide present in the solution.

The purpose of this study was to show the importance of enzyme shape on its ability to properly catalyze reactions by determining the effect of temperature on the specific enzyme peroxidase. Furthermore, the experiment aimed to determine the optimal temperature for peroxidase as well as to determine if the temperature effect is reversible. In order to test this, two test tubes containing pH 5 buffer with peroxidase and two test tubes containing H2O2 with the dye guaiacol were put into baths of either 4°C, 32 °C, and 60 °C as well as test tubes that were left at room temperature. Once the test tubes reached temperature they were all removed from their baths, and one of each mixture was immediately tested in a spectrophotometer while the remaining two were left to recover to room temperature and then tested after recovery. They were observed for two minutes at 20-second intervals.

By using acid-base titration, we determined the suitability of phenolphthalein and methyl red as acid base indicators. We found that the equivalence point of the titration of hydrochloric acid with sodium hydroxide was not within the ph range of phenolphthalein's color range. The titration of acetic acid with sodium hydroxide resulted in an equivalence point out of the range of methyl red. And the titration of ammonia with hydrochloric acid had an equivalence point that was also out of the range of phenolphthalein.. The methyl red indicator and the phenolphthalein indicator were unsuitable because their pH ranges for their color changes did not cover the equivalence points of the trials in which they were used. However, the

For this experiment, titrations on a weak acid, acetic acid, and a buffer were performed. Acetic acid was titrated with NaOH in order to observe the half-equivalence point as well as the equivalence point. Then, the buffer and the buffered acetic acid solution prepared faced additional titration with NaOH and HCl to evaluate the differing buffering effects following the addition of a strong acid and strong base. Finally, the buffer’s buffering capacity was calculated. If the experiment were to be repeated, it would be interesting to observe the buffering effects following a titration between a weak base and a buffer instead with greater concentrations. The change in the concentration following the preparation of buffer with a weak base and its conjugate acid would pose for an interesting experiment to observe an increase in the buffering capacity.

An acid-base titration is the determination of the concentration of an acid or base by exactly neutralizing the acid/base with an acid or base of known concentration. This allows for quantitative analysis of the concentration of an unknown acid