1 Apata 5 FINAL 1211K LAB REPORT MOSES APATA DESK DRAWER B40 July 16th 2024 UNKNOWN 2358921 BS 24 2 Apata 5 Abstract The main objective of the lab was to identify the identity of an unknown compound We did a lot of experiments for the class but only a few were important in determining the unknown acid identity And those experiments included the melting point and solubility of the unknown acid The other was the equivalent weight of the unknown acid in which we did three different titrations including titration of the HCL solution with NaOH solution where we tried to get a light pink solution with the help of phenolphthalein another titration with NaOH to determine the molarity of NaOH and the last titration was used to determine how soluble the acid was A PKa test was also done to go with the titration curve and finally a computer search was done to determine the exact name of the unknown acid Introduction The purpose of the experiments was to determine the identity of the unknown acid 2358921 Bs 24 An acid is a molecule or ion capable of either donating a proton or forming a covalent bond A base is a substance that can accept hydrogen ions in water and can neutralize an acid The main difference between an acid and a base is that an acid has a Ph level of anything less than seven and a base has a Ph level of anything greater than seven The base used for all experiments this semester was a NaOH solution in other words a sodium hydroxide solution An organic acid is an organic compound with acidic properties A titration is when a solution of a known concentration is used to find the concentration of an unidentified solution For the titrations done in this class which include KHP titration the purpose was to find out the molarity of the NaOH solution that was made The purpose of HCL titration is to find out the molarity of HCL which helps in determining the identity of the unknown organic acid There were other tests performed to determine the unknown acid including the melting point of the unknown organic acid and the PKA of the organic acid which then determines the identity of an unknown acid Experiments Five experiments went into determining the identity of the unknown acid The first was the melting point of the unknown organic acid The second experiment was the KHP and titration The third experiment of the HCL titration The fourth experiment was using the computer search to narrow down the list of possible compounds for the organic acid the fifth experiment was finding the correct PKa The organic acid The first experiment was done so the melting point of The organic acid could be found The first step of that experiment was inserting about 2 3mm of the organic acid into a capillary tube and obtaining an approximate melting point range of the unknown and that is done by setting the plateau to 260 degrees inserting the capillary tube and observing the tube until the organic inside starts to melt Record the initial temperature and when it stops melting to determine the melting point range The next step would be to select the approximate melting point range and fill a capillary tube with the standard compound and another with the unknown organic acid Insert both into the melting point apparatus and set the plateau to 10 degrees Celsius lower than the approximate melting point then hit start The final step would be to observe the capillary tube until it starts to melt record the temperature and then when the substance turns liquid record that temperature and that gives you the melting point range The second experiment was an HCL with NaOH This titration was done three times to have a very accurate reading The first step was to create the base with the NaOH solution The first part is to weigh enough solid NaOH so it can be dissolved in 800ml of DI water The next step would be to begin the HCL with NaOH titration The first step would be to use an automatic pipettor to deliver 10 00 ml of HCL solution into a 250 ml Erlenmeyer flask Add 20 ml of DI 3 Apata 5 water to the flask and a drop of phenolphthalein indicator solution the next step would be to add a magnetic stirring bar and place the flask on a stir plate Then fill the buret with NaOH solution and begin the titration Continue titration until the liquid in the flask turns light pink Repeat this experiment two more times and record each final volume The third experiment was the titration of KHP with NaOH to find the molarity of the NaOH solution This experiment is also done three times The first step is to weigh a sample of about 0 2xxx to 0 2xxxg of dried KHP and make sure to record four significant figures because it is very important for the calculations Transfer the dried sample to a 250ml Erlenmeyer flask and dissolve in 50ml of DI water Add a drop of phenolphthalein The next step would be to fill a burette with NaOH solution until it gets to the 0ml mark And be sure to take out air bubbles from the Burette Place the Erlenmeyer flask on a stirring plate put a magnetic stirring bar in the flask and begin the titration Begin titration with very small amounts of NaOH solution until the substance turns a faint pink color It Is important to know that the solution could turn pink at any point which is why a very small amount of NaOH solution is used at first When the solution is a faint pink color record the volume and repeat titrations two more times The fourth experiment would be the Equivalent weight determination The first step would be to weigh about 0 15xx 0 25xxg of the unknown organic acid Then dissolve the sample in 40 50ml of NaOH solution in a 250ml Erlenmeyer flask The next step would be to add a drop of phenolphthalein to the solution Then fill a burette with NaOH solution until it gets to the zero mark Place the flask on a stir plate and a magnetic stirring bar should be added to the flask then the titration should be done Record the data and calculate the equivalent weight The next experiment was the computer search done to narrow down the possible identities of the unknown organic acid The first the that was done was to go to the GSU chemistry website then the students option on the right hand corner which shows lab resources then to the chem 1211 resources and finally to hit the chem 1211 organic acid search engine The instructor s name should be entered then the corrected melting point then the equivalent weight and then hit search This brings up the list of possible identities of the organic acid show up At the end