Limiting Reactant Essay

In chemic responses, the significance of knowing the check reactant is high. In order to increase the part bear of inter member, increasing the confine reactant, possibly, is the most effective. In this experiment we were subject to calculate constricting reactants from the answer of CaCl2. 2H2O + K2C2O4.H2O(aq). As a group, we obtained our common flavor multifariousness of calcium chloride and kibibyte oxalate, and weighed the form. We were able to make an aqueous stem from the potpourri and distilled water. We boiled and separateed off the solution, leaving the precipitate. Once the precipitate was dried overnight, it was weighed and the kitty was measured. Then we reckon the ramparts of the precipitate. From these calculations, we established moles of the control reactant, were the same amount of moles in the product found on the stoichiometric on the wholey balanced equation. Next the pct retort of the limiting reactant was calculated. In spot B of this e xperiment, two solutions were added to the aqueous product in order to determine the limiting reactant. Once each solution was added, we were able to visibly see the precipitate forming when 0.5 M CaCl2 was added. This made us conclude the limiting reactant was in fact CaCl2. IntroductionStoichiometry is a section of chemistry that involves using relationships between reactants and/or products in a chemic reaction to determine desired quantitative data. Doing stoichiometry can calculate push-down listes, moles, and percents with a chemic equation. The use of stoichiometry is how we were able to invent the limiting reagent in this lab. We know that the limiting reagent is the chemic that bequeath be utilise up for the first time. Two factors affect the gestate of product in a chemical reaction the amounts of showtime materials and the percent yield of the reaction. Under au accordinglytic conditions such as temperature and pressure, can be adjusted to increase the yield of a desired product in a chemical reaction but because the chemicals react according to fixed mole ratios, only a limited amount of product can form from measured amounts of starting materials. A way for us to better understand this concept of the limiting reactant is to observe the reaction in our experiment. The reaction of calcium chloride dehydrate, CaCl22H2O,and potassium oxalate monohydrate, K2C2O4H2O, in an aqueous solution.For the reaction system in this experiment, both the calcium chloride and potassium oxalate are soluble salts, but the calcium oxalate is insoluble. The ionic equation for the reaction is Ca2+(aq)+2Cl-(aq)+2K+(aq)+C2O42-(aq)+3H2O(l)CaC2O4H2O(s)+2Cl-(aq)+2K+(aq)+2H2O(l) impersonateing only the ions that show evidence of a chemical reaction, formation of a precipitate, and by removing the spectator ions, no change of ionic form during the reaction, we consent the net ionic equation for the observed reaction is Ca2+(aq)+ C2O42-(aq)+H2O(l)CaC2O4H2O(s). In Par t A of this experiment the solid reactant salts CaCl2H2O forms and K2C2O4H2O form manifold garland of noncitizen composition. The concourse of the solid mixture is measured and then added to water-insoluble CaC2O4H2O forms. The CaC2O4H2O precipitate is collected by gravity filtration and dried, and its mass is measured. In Part B, the limiting reactant for the formation of solid calcium oxalate monohydrate is hardened from two precipitation visitation of the final reactant mixture from Part A. The first political campaign we tested the mixture for an excess of calcium ion with an oxalate reagent and the second test the mixture is tested once again for an excess of oxalate ion with calcium reagents. Materials and MethodsMaterialsresearch laboratory finishingSafety goggles1 250ml beaker1 piece of extend constitutionfunnel1-2 grams of salt mixtureA hot plateA weighing subdueMethods1. sampleers obtained one 250 ml beaker and weighed it on the weighing scale and preserve th e results2. The 250 ml beaker was then filled with 1-2 grams of the salt mixture and weighed again3. 100 ml of distilled water was added to the salt mixture4. The beaker was placed on the hot plate and brought to a boil then removed5. by and by cooling, the experimenters come homeed the mixture using the puree paper and funnel6. Experimenters left the filter paper to air dry overnight7.The air dried filter paper was then placed on the weighing scale and results were recorded ResultsIn experiment A the results from the precipitation of CaC2O4 H2O from the salt mixture were obtained by weighing the items listed on Table 1 on a scale. Table 1.Mass of Beaker (g)102.994gMass of Beaker and flavour Mixture104.683gMass of Salt Mixture (g)1.689gMass of Filter composing (g)1.336gMass of Filter Paper and CaC2O4 H2O (g)2.000gMass of Air-Dried CaC2O4 H2O (g)0.664gIn Experiment B the limiting reactant was determined to be CaCl2 when two drops of the test reagent 0.5 M CaCl2 was added to the supernatant liquid in test tube 1, and a precipitate formed. Since in that respect was a reaction, there was C2O42- in excess and Ca2+ is the limiting reactant in the skipper salt mixture present in test tube 1 . This was further confirmed when two drops of the test reagent .05M K2C2O4 was added to the supernatant liquid in test tube 2. There was no precipitate because Ca2+ was not present since it was the limiting reactant and instead C2O42- was in excess. Table 2.Moles of CaC2O4 H2O precipitated (mol).0045 (mol)Moles of limiting reactant in salt mixture (g)CaCl2 .0004 (mol)Mass of limiting reactant in salt mixture (g)CaCl2 .4995 (grams)Mass of excess reactant in salt mixture (g)Ca2C2O4 1.113 (grams)Percent limiting reactant in salt mixture (%) CaCl34% (34.1%)Percent excess reactant in salt mixture (%) K2C2O466% (65.8%)DiscussionThe data of the mass of the salt mixture was a big key for finding the moles of CaC2O4 precipitated. The submarine mass of CaC2O4 H2O was 146.097 grams. The mass of the air-dried CaC2O4 H2O CaCl2, was .664g as recorded in table 1. Using a calculation of .664 x 1 mole / 146.097 a result of .0045 mol was recorded in table 2. The test done in Experiment B allowed us to know without or so(prenominal) calculations that Ca2+ is the limiting reactant. This allowed us to conclude that the moles of the limiting reactant were .0004 (mol) of CaCl2. In order to action the grams of the limiting reactant, the moles of the limiting reactant must be multiplied by the poor boy mass of the limiting reactant.Therefore the mass of the limiting reactant was .0045 moles and multiplied by its molar mass of 111g to result in .4995g of the limiting reactant in the salt mixture. Next the mass of the excess reactant in the salt mixture was calculated using the same method as the limiting reactant except the molar mass of the excess reactant was used to result in 1.113 (grams) Ca2C2O4 . The final standard in the process was to find the percent by mass of the limiting reactant. Since Experiment B allowed us to determine that Ca2+ is the limiting reactant, therefore to find the percentage composition it is necessary to divide the limiting reactant mass by the mass of the original sample then multiply by 100. This provided a result of 34%, and to find the excess percentage, this value was subtracted from 100 to yield 66% of K2C2O4 as the percent of excess reactant in salt mixture. wrongdoing AnalysisPossible errors might be attributed to careless errors in read the scale to measure the mass of the beaker, salt mixture or filter paper. Even whenproper care is taken in reading the instruments, authoritative errors can present themselves in the instrument used to measure mass. Here, a calibrated scale was used to measure mass, and the systematic error is unknown since it is one of the hardest errors to detect. These two sources of errors might help explain the .1% missing from the CaCl2 and K2C2O4 salt mixture recorded in Table 2.Prec ision and Accuracy spot accuracy deals with how close a measured value is to a received or accepted one, precision deals with how reproducible a given standard is. Here the mass of the beaker, salt mixture, and filter paper are all precise because they are easily reproducible since it simply involves putting the items on a scale. If the process was repeated 50 times the results would not spay or at the least by .0001 grams based on some outside factor. The mass of the air-dried CaC2O4 H2O is accurate because it was calculated as true by subtracting the mass of the filter paper from the mass of the filter paper and the CaC2O4 H2O. ConclusionAs we have stated previously, CaCl2 was our limiting reactant based on the precipitates observed. We were able to rule out Ca2C2O4 because of the lack change in our precipitate..It was important to note that a limiting reactant in a chemical reaction limits the amount of product that can be formed. The reaction will stop when all of the limitin g reactant is consumed. The excess is the reactant in a chemical reaction that remains but there is nothing with which it can react. fetching this knowledge we have gained in becharmly observing the results, we can view as it to future experiments in chemistry in order to evaluate how oft product one might want to produce in a given chemical reaction.Reviewing other experiments, from other schools, it is apparent that the need for appropriate data collection in this type of experiment, will help in identifying the excess and limiting reagents. As was the case in UCCSs Chem 103 Lab Manual, following the procedures and doing them in the proper order are vital to ensuring victory in proper reactions.ReferencesTro, Nivaldo. Chemistry A Molecular Approach. 3rd ed. Boston, MA Pearson Education, Inc.Beran, J. A. research laboratory Manual for Principles of General Chemistry. 8th ed. Hoboken, NJ John Wiley & Sons, Inc. 2009 Beran, J. A. Laboratory Manual for Principles of General Chemi stry. 9th ed. Hoboken, NJ John Wiley 2010 UC Davis ChemWiki. Stoichiometry and Balancing Reactions. http//chemwiki.ucdavis.edu/Analytical_Chemistry/Chemical_Reactions/Stoichiometry_and_Balancing_Reactions UCCS Chem 103 Laboratory Manual. Experiment 3 Limiting Reactants. http//www.uccs.edu/Documents/chemistry/nsf/103%20Expt3V-LR.pdf Masterson, W, Hurley, C. Chemistry Principles and Reactions. 6th ed. Belmont, CA abide/Cole Cengage Learning 2009.