Purpose The purpose of this experiment is to use our knowledge from previous experiments to determine the theoretical, actual, and percent yields of the lead chromate from the reaction of solutions of potassium chromate and lead nitrate (Lab Guide pg. 83). Question or Problem The question that was proposed for investigation was: Can the theoretical, actual, and percent yields be determined accurately (Lab Guide pg. 83)? Background Discussion For this experiment we have to use physical methods to separate the reaction mixture from the liquid. The physical methods that were used are filtration and evaporation. Filtration is the separation of a solid from a liquid by passing the liquid through a porous material, such as filter paper. Evaporation is when you place the residue and the damp filter paper into a drying oven to draw moisture from it by heating it and leaving only the dry solid portion behind (Lab Guide pg. 33.). Sample Calculations In this experiment there were eight different equations used and they were, molecular equation, total ionic equation, net ionic equation, calculating the number of moles, calculating the theoretical yield and limiting reagent, calculating the mass of〖PbCrO〗_4, calculating actual yield, calculating percent yield (Lab Guide pg.83-85). Molecular Equation:K_2 CrO_4 (aq)+Pb(〖NO〗_(3)) /2→〖PbCrO〗_4 (s)+2KNO_3 (aq) Total Ionic Equation: 〖2K〗^+ (aq)+〖CrO〗_4^(2-) (aq)+〖Pb〗^(2+) (aq)+ 〖2NO〗_3 (aq)→〖PbCrO〗_4 (s)+ 〖2K〗^+ (aq)+〖2NO〗_3^- Net Ionic Equation: 〖Pb〗^(2+) (aq)+〖CrO〗_4^(2-) (aq)→〖PbCrO〗_4 Calculating the Number of Moles: Number of moles of〖 K_2 CrO〗_4, mol = (4.0 ×〖10〗^(-2) mol L^(-1))(5.0×〖10〗^(-2) L)= 2.0×〖10〗^(-3) mol Number of moles〖Pb(NO〗_3)/2, mol = (8.0 ×〖10〗^(-2) mol ... ... middle of paper ... ...form 〖PbCrO〗_4 and then process it through a filter. After filtering the 〖PbCrO〗_4 I had to dry the 〖PbCrO〗_4 residue in the drying oven for 30 minutes at 80℃. Then let it cool for 5 minutes and weigh it and finally make a few calculations to obtain the theoretical, actual, and percent yields of 〖PbCrO〗_4. I was able to fulfill the experiment because I obtained all the answers to the equations in an accurate amount. I believe this experiment was a success due to my hypothesis of, If physical methods are used to separate 〖 PbCrO〗_4 precipitate from the reaction mixture then I can successfully calculate the theoretical, actual, and percent yields, being correct. Works Cited Neidig, H. A., and J. N. Spencer. "Precipitating Lead Chromate on a Small Scale." General Chemistry For Engineering And Science. Mason: Cengage Learning, 2012. 83-90. Print. Signature Lab Ser.
The purpose for this experiment was to determine why it was not possible to obtain a high percent yield when Calcium Nitrate Ca(〖NO_3)〗_2 with a concentration of 0.101 M was mixed with Potassium Iodate KIO_3 with concentration of 0.100 M at varying volumes yielding Calcium Iodate precipitate and Potassium Nitrate. Filtration was used to filter the precipitates of the solutions. The percent yield for solution 1 was 87.7%, and the percent yield for solution 2 was 70.8%. It was not possible to obtain a high percent yield because Calcium Iodate is not completely soluble and some of the precipitates might have been rinsed back to the filtrates when ethanol was used to remove water molecules in the precipitate.
The experiment was not a success, there was percent yield of 1,423%. With a percent yield that is relatively high at 1,423% did not conclude a successful experiment, because impurities added to the mass of the actual product. There were many errors in this lab due to the product being transferred on numerous occasions as well, as spillage and splattering of the solution. Overall, learning how to take one product and chemically create something else as well as how working with others effectively turned out to be a
Once the mixture had been completely dissolved, the solution was transferred to a separatory funnel. The solution was then extracted twice using 5.0 mL of 1 M
For this experiment, you will add the measured amount of the first sample to the measured amount of the second sample into its respectively labeled test tube then observe if a reaction occurs. In your Data Table, record the samples added to each test tube, describe the reaction observed, if any, and whether or not a chemical reaction took place.
The % composition by mass of oxygen in Potassium Chlorate was found to be 43.4%.
The purpose of this lab was to to cycle solid copper through a series of chemical forms and return it to its original form. A specific quantity of copper undergo many types of reactions and went through its whole cycle, then returned to its solid copper to be weighted. We observed 5 chemical reactions involving copper which are: Redox reaction (which includes all chemical reactions in which atoms have their oxidation state changed), double displacement reaction, precipitation reaction, decomposition reaction, and single displacement reaction.
Going into details of the article, I realized that the necessary information needed to evaluate the experimental procedures were not included. However, when conducting an experiment, the independent and dependent variable are to be studied before giving a final conclusion.
Use glassware as directed by your instructor. Place a test tube placed inside a beaker with ice water to collect the product from the apparatus. Obtain the 10mL round bottom flask from the apparatus. Obtain two graduated cylinders of 10mL. On one graduated cylinder measure 4mL (85% H3PO4) of Phosphoric Acid and pour into the 10mL round bottom flask. On the other graduated cylinder measure 3mL of Cyclohexanol and pour into the flask as well. With a pipet add 5 drops of Sulfuric Acid (H2SO4) into the flask. Attach the round bottom flask to the distillation apparatus. Place thermometer with rubber stopper on the apparatus to obtain the temperature Start with the water flow through the condenser. Turn on and heat the reaction until the product starts to distill. Distill and collect until thermometer temperature rises to 85˚C. Once there is no more product to collect obtain the test tube of product. Two layers should be formed, top layer of cyclohexane and bottom layer with water. Obtain a pipette and remove the bottom layer (water) if any. Add 10% (5mL) of Sodium Bicarbonate (NaHCO3) to nuclearize any acid in the solution. Mix well and remove once again the bottom layer of water with pipette. Add 5mL of water and mix well to wash the top layer. After the two layers form again, remove entirely the bottom layer of water and add a few pellets of Calcium Chloride. Obtain a 50mL or 100mL beaker and weigh.
A precipitation reaction can occur when two ionic compounds react and produce an insoluble solid. A precipitate is the result of this reaction. This experiment demonstrates how different compounds, react with each other; specifically relating to the solubility of the compounds involved. The independent variable, will be the changing of the various chemical solutions that were mixed in order to produce different results. Conversely the dependent variable will be the result of the independent variable, these include the precipitates formed, and the changes that can be observed after the experiment has been conducted. The controlled variable will be the measurement of ten droplets per test tube.
Theoretical yield is the maximum amount of product that can be produced during a reaction (French et al. 83). The numbers used to find theoretical yield must be those of the limiting reagent (French et al. 83). Because parts of the material used are inevitably lost during experiments, the actual yield will be smaller than the theoretical yield (French et al. 83). To test the efficiency of the reaction, calculate the percent yield as shown below:
In stoichiometry and this lab, proportions or mass ratios are used to find the quantitative relationships between the reactants and products. Another topic that relate to this lab is the limiting reaction. Stoichiometry was used to find the limiting reaction of this reaction lab through proportions and conversions, which was lead (II) nitrate. Additionally, the excess reactant is another topic that relates to this lab. Stoichiometry was used to find the excess reactant which was potassium iodide. Another topic mentioned was the actual yield. The actual yield was used for lead (II) iodide. This data can be compared to the theoretical yield to find how well the experiment was performed. Additionally, the theoretical yield was used in this lab in order to find the percent yield. Another topic was the percent yield. The higher the percent yield, the better the experiment was performed. Another topic was double replacement. In the experiment the reactants are made of two elements that yields products which have been double replaced. In addition to the previous topics, uncertainty is another topic repeatedly used throughout the lab. The uncertainty is used during measurements to account for the room of error that was possibly made during the measurements. Molar mass was another topic that relates to the lab. In the proportions and conversions part of the lab, molar mass is used to correctly balance the
Following is a short and understandable explanation of the methods used in the paper and also an explanation of the experiment that was performed to reach to conclusions in the paper.
On repeating this experiment more care should be taken when purifying to remove the solvent impurities and minimise loss of crude product.
Once we know all the values of the ingredients, the value can be multiplied by the
A. a 0.112 per cent w/v solu-tion of orthophosphoric acid adjusted to pH 7.0 using a 4.2 per cent solution of sodium hydroxide,