Preparation of a Salt (Lead Iodide) by Using Precipitation Method.

The theoretical yield for the product is a necessary component in finding percent yield, and Eq. 2 and Calculation 2 demonstrate how it was found.

The lead in the environment is formed naturally in the earth’s crust mainly as Lead Sulphide. The main exposure channels of lead entering the environment through atmospheric lead is predominantly from automobile emissions. Other lead exposure routes include lead-acid batteries, paint chips, fertilizers, utilized ammunition, pesticides, and other industrial byproducts. The means of conveying lead from key emission sources is mainly through the air. Concerning the sources of lead in drinking water, normally lead reaches into the residents’ water after it is channeled from their water treatment plant or the wells. To be more precise, the source of lead in people’s water supply largely emanates from their households’ pipes or lead solder from plumbing. The most typical cause of the lead formation is from the corrosion reaction by the lead pipes or solders and the water. The acidity as a result of the low pH, dissolved oxygen, and little mineral contents in the water are main reasons of the corrosion. The lead amounts in the water become high if the water spends a long duration of time stagnated inside the old pipes.

Usually, the percent is a good amount less than 100 because of multiple factors including transfer between different lab tools and when an unfulfilled reaction takes place. In the case of this experiment, copper most likely was lost between transfers of the Copper (II) solution, although loss was attempted to be minimized. Also, after the reaction, the copper was filtered and some mass could have lost if the reaction was not fully carried out and all of the copper did not precipitate out of the solution. But, when the copper oxidized overnight on the heater, the reaction with oxygen added mass to the ending mass of copper. These areas of losing and gaining mass throughout the procedure equaled out in the end because the percent yield was very close to 100% as the actual yield was 0.7 grams of copper and the theoretical yield was 0.71 grams of copper. If the copper did not oxidize, it is believed that the percent yield would not have been as close to 100% as it was because the oxygen gave mass back that was lost along the way of the

12. Determine the percent error using the equation and knowing that the actual specific heat of lead is 0.130 J/g(oC): (10 points)

Weight 30 dry pre-82 pennies which get 89.77g, using 30ml initial volume measuring the volume of 30 pennies, record the data 10.0ml. Using equation Density= Mass/Volume, get the density of the pre-82 pennies is 8.98g/ml. Then calculate the error%=0.10%, and the deviation%=1.29%.

1. Suggest at least one chemical reason why your percent yield is less than 100%. (Incomplete reactions? Side reactions? Stability of reagents?)

In some instances lead reacted very similarly with the alkaline earth metal but very different in the other reactions such as with iodide. This is due to lead’s position on the periodic table as compared to those of the alkaline earth metals. The position on the periodic table correlates to an element’s atomic radius, ionization energy, and electron affinity. All of these properties affect an element’s chemical properties such as solubility. A systematic error occurred during my experiment when I observed a reaction between barium and iodide. There should have been no reaction. This error is probably the result of using a test tube that was not cleaned properly prior to combining Ba(NO3)2 with NaI. This experiment reinforced the concepts introduced in Chapter 8 of our textbook.

Batteries: The major usage of lead is making storage batteries. The grey colour negative electrode is made of Pb and the red colour on the positive electrode is PbO2 in the battery. Airplanes, automobiles, electric vehicles, trucks, tanks, and broadcasting station all use the storage batteries as the energy source of light and making one battery needs dozens of kilograms of lead (Crompton 2000).

The major sources of lead here were gasoline, paint chips and water from old plumbing. After lead was removed from gasoline and paint, blood lead levels (BLL) in children decreased on average from 16 mcg/dL to less than 3 mcg/dL. Residual lead persists in the environment, however. A toxic level is currently defined as 5 mcg/dL. In U.S. children age 1-5, the prevalence of BLLs >10 mcg/dL decreased from 88% to 4.4% between 1976 and 1994 and further dropped to 0.8% by 2010. Yet there are still almost half a million children in the U.S. with levels >5

12. Determine the percent error using the equation and knowing that the actual specific heat of lead is 0.130 J/g(oC): (10 points)

Before the synthesis of the Copper Iodine Compound, the identities provided (CuNO3)2 and Nal weighed 1.65 g and 4.7 g, respectively. After being weighed, the (CuNO3)2 exhibited a blue color, while the Nal, through observation, was a white color. However, when both identities were combined, the product turned into a brown and red rocky material. Once 20 mL of deionized water was added, the product quickly turned pale pink paste. After the solution was repeatedly washed with a total of an additional 100 mL of deionized water, the product was powdery and pink with small grains, and was left to air-dry. Once the product was air dried, it was observed to be a pale pink color, while the filter paper was stiff as the product was hard and dry. Therefore, the solid was scraped off onto a recrystallizing dish. However, the mass of an empty recrystallizing dish needed to be recorded in order to compare how much of the synthesized copper iodide was obtained. Within this case, the empty recrystallizing dish used weighed 32.01 g, the product on the empty dish weighed 1.03 g, having a total weight of 33.04 g.

Purpose: The purpose of this experiment was to observe the many physical and chemical properties of copper as it undergoes a series of chemical reactions. Throughout this process, one would also need to acknowledge that even though the law of conservation of matter/mass suggests that one should expect to recover the same amount of copper as one started with, inevitable sources of error alter the results and produce different outcomes. The possible sources of error that led to a gain or loss in copper are demonstrated in the calculation of percent yield (percent yield= (actual yield/theoretical yield) x 100.

Lead, a naturally occurring metal and can be used in almost everything. It can cause serious health issues if it is exposed for a long time, particularly in children as they are more susceptible to absorbing and retaining lead in their bodies. Each year, in the United States 310,000 of 1- to 5-year age group are found to have unsafe levels of lead in their blood, which can cause a wide range of symptoms. (1)

2.68 0.75 69.69 4.83 105.26 50.56 94.69 135.65 6.58 1.24 0.71 0.64 4.84 1.30 41.97% 16.13% 8.32% 12.99% 35.22%

= (89.14 + 83.72 + 82.7 + 86.54 + 93.87 + 88.88 + 92.5 + 90 + 97.5) ÷ 9