Standardization Chemistry Lab Report

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

The color of the solution was turning slightly into yellow and the color of the iron strip into white.

A few sources of potential error are as follows: loss of product on glassware throughout the experiment, inadequate measuring of chemicals, "impure" chemicals being worked with, and loss of final product during crystallization processes.

3.0g of salicylic acid was weighed then 3.0mL of acetic anhydride and 6 drops of 85% H3PO4 were added to it. The mixture was warmed over a water bath for 5 minutes while stirring. After warming, 20 drops of distilled water was slowly added. 15mL of water was added then the solution was heated until it became clear. It was allowed to cool and was placed in an ice bath until the solution becomes cloudy. Using pre-weighed filter paper, the mixture was filtered and was allowed to dry in the filter paper.

Add 3 drops of iodine solution * Shake it well,

A cold, wet pipe cleaner was then added to the top of the reaction flask to keep the column cold which caused no vapors to rise into the column.

Discard the solution in the appropriate container as directed to you by your lab instructor.

3.6.3. 2, 4 – D (2, 4–Dichloro phenoxy acetic acid) stock solution (1mg/ml): 10.0mg of 2.4-D being weighed and dissolved completely in 1N NaOH to a final total volume

If an air bubble was present in the buret during titration, it would affect the calculated molarity of the HCl. The air bubble takes up volume in the buret, making the volume of NaOH in the buret artificially high. If the bubble came out during titration, then the volume of the NaOH added would appear to be higher than what it actually was, and would ultimately result in the calculated HCl concentration be higher than what it actually

However, this was not the case. Discrepancies occurred between the two sets of values due to experimental errors. Some of the sources of error during the experiment include: drift on the voltmeter that affected the accuracy of measurements (instrumental error), rounding-off errors during calculations and the old resistance box. However, these errors can be eliminated by using a new functional resistance box, recording readings at right angles, and using four decimals in calculations to avoid rounding off errors.

14) Let the crystals of the silver settle in the plastic container and decant off the liquid.

One milliliter of 6.00-M phosphoric acid was placed into a 125-mL Erlenmeyer flask using a volumetric pipette. Using a slightly larger pipette, six milliliters of 3.00-M sodium hydroxide was transferred into a 50-mL beaker. Then a disposable pipette was used to slowly mix the sodium hydroxide into the phosphoric acid while the solution was swirled around. Then both the beaker and flask were rinsed with 2-mL of deionized water and set aside. A clean and dry evaporating dish was weighed with watch glass on a scale. Then the solution was poured into the dish and the watch glass was placed on top. The solution was then heated with a Bunsen burner to allow for the water to boil off to reveal a dry white solid. After the dish cooled to room temperature it was once again weighed and the new mass was recorded.

For example, when dissolving the samples, too much liquid could have been added, affecting how saturated the solution was, and ultimately affecting the accuracy of the results. To prevent such an error, one could gradually add water and patiently mix the solution to make a saturated solution. Additionally, errors could have come from not making a solution as close to 1.0 M of the compound. In order to prevent this possible error, one could have calculated the volume of the water (in mL) needed to make the 1.0 M solution, which would result in having more precise results. Lastly, being that there are multiple calculations involved, being careful and observant in correctly recording the values could prevent simple

In this experiment, a redox reaction occurred. An oxidation-reduction reaction (redox) is a type of chemical reaction that involves a transfer of electrons between two solutions. The chemical being oxidized is losing electrons and the chemical being reduced is gaining electrons. In this case KMnO4 is losing electrons and Oxalic Acid is gaining electrons. KMnO4 can titrate a or reduce Oxalic acid. Titration is the technique used to find the unknown concentration of one solution based on the concentration of a known solution. In equation 2, the molar relationship between the 2 is shown, it is 2 KMnO4 to 5 Oxalic Acid. The molar ratio relationship is useful because it shows how much of a certain product is needed to help a reaction occur and which chemical is limiting reagent. The experiment was started by preparing a titrating strength KMnO4 solution from stock to a less concentrated KMnO4. Equation one shows how this was done. The KMnO4 needed to be diluted, if it had not been diluted, then it would be way too hard to get an accurate reading of the Oxalic Acid used. Without being diluted the Oxalic Acid would be strong. The next step was to standardize the KMnO4 solution. It was calculated that 37.5 mL of Oxalic Acid could titrate 15 mL of KMnO4. To determine the exact molarity of a solution a standardization needs to happen. In this experiment the standardization found how much Oxalic acid was needed. Through the controlled variable, the fact that 37.5 Oxalic acid could be titrated by 15 mL of KMnO4, the percent of the

Sodium hydrogen carbonate was added to the solution until it becomes neutral. Ph paper was used for this test to determine its ph value.