Theoretical and Experimental Yields of PbNO3-KI Reaction

and wait for it to boil.

PbI2 is a yellow substance that is insoluble.In the lab the precipitate was boiled and the substance became soluble. This was caused by heat, it can increase the solubility of substances because when you boil the substance it can be formed into a liquid which makes it soluble. The percent yield of 2KNO was much higher than the percent yield of PbI2.

The percent yield of PbI2 was 8. 04% while the percent yield of 2KNO was 77. 4%. The percent yield of Potassium Nitrate (2KNO) was considerably higher than the percent yield of Lead (II) Iodide (PbI2).

This will be explained further in the error analysis section.During this lab the substances go through a process of separating, collecting and purifying. During that process the substances go from solids to a liquid then back to a solid. This is because the PbI2 has to become heated so it can be soluble enough to pass through the funnel. That was the separating process where the crystals are going to be separated from the solution.

This cycle is repeated several times to get the best yield percentage possible. The crystals

collected on the filter paper had to be placed into the drying oven so it can be turned back into a solid and able to be weighed for mass.That made this experiment very tricky and difficult because the goal was to get the best yield percentage possible. The KNO3 was separated from the water so it also could be weighed for mass; this was the easiest one to do because all that needed to be done was boil the solution until all the water has evaporated.

Error. There are several possible errors that could occur during this lab. The main reason that could cause the accuracy of the results is transfer loss. Every time the substance changed containers, a small amount of the product was lost.The percent yield is calculated assuming that 100 percent of the product is still there. This lab was performed carefully although small accidents happen like minor spills which all affect the results in the end. Another possible error could be human error, there could of been an error when a measurement was taken or read, and also in the calculations, this could result in throwing the results off drastically.

Conclusion

After this lab it was found that the theoretical yield of PbI2 was 1. 99g and the theoretical yield of KNO3 was 0. 879g. The percentage yield of PbI2 was 8. 04% and the percentage yield of 2KNO3 was 77.%. This lab had a few mistakes that threw off the final results but the procedure was done correctly and it still shows the knowledge of how to do the calculations and steps.

Analysis

Pb(NO3) + 2KI= PbI2 + 2KNO3 331. 21 g/mol 332 g/mol 460.

99 g/mol 202.22 g/mol

Theoretical yield of PbI2 1. 44/331. 21 g/mol = x/460. 99 663. 8256= 331.21x

PbI2= 2. 00g 1. 44/332=x/460. 99 663. 825=332x PbI2=1.99g

Theoretical Yield of KNO3 1. 44/331. 21=y/202. 22 292. 196=331. 21y KNO3=0.879g 1. 44/332=y/202. 25 KNO3=0. 88g

Percent Yield of PbI2 0. 16/1.99 x100% =8. 04%

Percent Yield of KNO3 0. 68/0. 879 x100% =77. 4%