Investigating Stoichiometry Essay

Quantitative DataThe table shows the pile of reactants super C iodide and lead(II) nitrate, and the mass of the come devour from the reaction between KI(aq) and Pb(NO3)2(aq). stack of lessen from reaction between KI(aq) and Pb(NO3)2(aq) throne of chiliad iodide (0.001g)1.701Mass of lead(II) nitrate (0.001g)1.280Mass of tense up publisher (0.001g)0.798Mass of precipitate + dribble authorship (0.001g)2.525Mass of precipitate (0.001g)1.727Qualitative Data1) by and by displace the KI(aq) and Pb(NO3)2(aq) solution together into the beaker, a churl terminal was use to stir the solution so as to make certain(a) it was conglomerate properly. However, after intake, when the glass rod was taken out, there were sm every(prenominal) amounts of precipitate (PbI2(s)) stuck onto the glass rod, and could not be removed.2) While gushing(a) the remaining ad multifariousness into the filter paper, not in all the mixture was poured into the filter funnel and paper. Some of the mixtur e was stuck in the beaker even after trying to backwash it down piss and scooping it out with the glass rod.3) after filtrating the mixture, it was observed that there were whatsoever parts of the separate that was still yellow in colour, with any(prenominal) PbI2 crystals natation around, which meant that about of the resi collectible (PbI2) passed through the filter paper. regular(a) so, another round of filtration was not carried out.The chemical compare obtained from the reaction above2KI(aq) + Pb(NO3)2(aq) 2KNO3(aq) + PbI2(s)Step 1) Using stoichiometry, signal the mass of PbI2(s) formed when a solution containing 1.701g of KI(aq) is mixed with a solution containing 1.280g of Pb(NO3)2(aq)First, the limiting reagent is determined by finding out which reagent produces lesser molees of PbI2.Using Pb(NO3)2 Moles of Pb(NO3)2 = 1.280g Pb(NO3)2 x= 0.0038646176mol Pb(NO3)2Moles of PbI2 = 0.0038646176mol Pb(NO3)2 x= 0.0038646176mol PbI2Using KI Moles of KI = 1.701g KI x= 0.0102 46988mol KIMoles of PbI2 = 0.010246988mol KI x= 0.005123494 mol PbI2?Pb(NO3)2 is the limiting reagent.Second, we predict the mass of PbI2 formed.Mass of PbI2 = 0.0038646176mol PbI2 x= 1.781550067g PbI2 1.782g PbI2Step 2) nowadays we calculate the unquestionable mass of PbI2 formed.Mass of filter paper = 0.798gMass of precipitate (PbI2) + filter paper = 2.525gMass of PbI2 produced = 2.525g 0.798g= 1.727gStep 3) Now we calculate the pct dampen.Percent yield of PbI2 = PbI2 x 100%= 96.91358025% 96.9%Analysis of ResultsAfter conducting the experiment, it is found that the per centum yield of PbI2 produced was 96.9%, which was rather accurate. However, it was cast down than the predicted mass by 3.1%, which could be due to the qualitative results shown above, random errors and inaccuracy of the experiment.When stirring the KI(aq) and Pb(NO3)2(aq) solution, some of the PbI2 precipitate was stuck onto the glass rod used for stirring, and could not be removed without using fingers, whi ch would extradite got contaminated the solution. This resulted in the decrease in the actual mass of PbI2 precipitate measured, causing the percent yield to be slightly lower than the predicted yield.When pouring the mixture into the filter funnel, not all of the mixture was poured into the filter paper as some of it was stuck inside the beaker. even up though water was used to wash some of the mixture stuck in the beaker into the filter paper, not all of the mixture was filtered. The mixture stuck in the beaker and was not filtered would get down decreased the percent yield.Finally, when the mixture was being filtered, some of the PbI2 precipitate passed through the filter paper and went into the filtrate. The filtrate was not filtered again, so some of the PbI2 was not figure into the final mass of PbI2 produced. This would feature decreased the percent yield as well.All the above would arrest contributed to the fact that the percent yield was 3.1% lower than the predicted yield. certaintyThe results from the experiment showed that the percent yield of PbI2 is 96.9%, which is rather accurate. However, due to random errors and the qualitative results shown above, the percent yield is 3.1% lower than the predicted yield.Limitations and ImprovementsIf I could do the experiment again, As some of the precipitate was stuck onto the glass rod and could not be removed by using my fingers, I could guide just used a little subroutine of water to wash it down back into the mixture. This would have decrease the difference in the percentage between the predicted yield and the percentage yield. Even though water was used to wash some of the mixture into the filter funnel, there was still some mixture stuck in the beaker. The process of using water to wash down the mixture could have been repeated everywhere and over until all the mixture is in the filter funnel. After filtrating the mixture once, some of the PbI2 crystals went through the filter paper and into the filtrate in the conical flask. To make sure all the PbI2 precipitate is counted towards the percent yield, the filtrate could have been filtrated again at least 2 much times. This would have increased the mass of PbI2, which would have do the percent yield closer to 100%.