II.Data Collection and Processing
A. Data Collection
Amount of Substance (g) Uncertainty ±0.01g| Water Added (mL)Uncertainty ±0.05 cm3 (mL)| 3.30 g Pb(NO3)2| 50.00 mL|
4.00 g KI| 50.00mL|
11.90 ±.06 g PbI2 (The uncertainty of this value differs from the uncertainty value of the other masses) | N/A|
The qualitative data taken was that the compound created was a yellow precipitate, and when the water was poured through the funnel in order to strain the precipitate, it retained much of it, making the ending mass of the precipitate far more than the Theoretical yield (4.60 g, which is a percent error of about 259%). The two substances mixed together (Pb(NO3)2 and KI) were white in color, and resembled a sort of powdery substance.
B. Data Processing and Presentation
The theoretical yield stated above (4.60 g) was calculated by finding the appropriate amount of moles of the substance in a balanced equation (1 mole) and using stoichiometry to find out the number of moles that are in the actual equation with the quantities used. This value came out as 4.60 g and is used for the theoretical yield.
The average mass of the filter paper, a value used to determine the mass of the final precipitate, (1.01 ± 0.05 g) was found by using the formula (0.97 + 0.99 + 1.06) / 3.00, and came out to the value 1.01 g.
Mass Taken with Filter Paper| Average mass of Filter Paper| Actual Yield| 12.91 ± 0.01 g| 1.01 ± 0.05 g| 11.90 ± 0.06 g|
The actual yield was found by subtracting the average mass of the filter paper (1.01 ± 0.05 g) from the mass value received when the mass of the precipitate in the filter paper was taken (12.91 ± 0.01 g). This value is represented as the mass of the precipitate in the table above as 11.90 ± 0.06 g.
The percent uncertainty of the measurements taken for the mass of the reactants, the volume of the water, and the final reaction are as follows (respectively):...