Lab Report Percent Yield

| Percent Yield Lab | | | | 4/20/2012 |
Mrs.Sardella
Per4
Matt , Kait
Mrs.Sardella
Per4
Matt , Kait

|

Introduction
*Limiting Reactant: A reactant that is completely consumed during a chemical reaction, limiting the amount of product that is produced.
*Excess Reactant: A reactant that remains after a reaction is over.
*Theoretical Yield: The amount of product that is predicted by stoichiometric calculations
*Actual Yield: The amount of product that is recovered after a reaction is complete.
*Percentage Yield: The actual yield of a reaction, expressed as a percentage of the theoretical yield.
The equation for calculating the percent yield of a reaction is:
Percentage Yield = Actual Yield X100% Theoretical
m=?
Mm (39.1)+(126.9) (317.2) (39.1) +(14) + (16x3) (207.2)+(126.9x2) =166g/mol 331.2g/mol 69.4g/mol 461.0g/mol
#n (EQUN) 2 mol 1 mol 2mol 1mol
M of PbI2 w KI = 1.25g KI X 1mol KI X 1 mol PbI2 X 461.0g PbI2 = 1.735 g of PbI2 LR 166.0g KI 2 mol KI 1 mol PbI2

M of PbI2 W Pb(NO3)2 = 1.25 g Pb(NO3)2 X 1 mol Pb(NO3)2 X 1 mol PbI 2 X 461.0 g PbI2 331.2 g Pb(NO3) 2 1 mol Pb(NO3)2 1 mol PbI2 =1.739 g od PbI2
3.The theoretical yield of the precipitate in the reaction is 1.735 g of potassium iodide.
Observation Table Material | Mass with no substance | Mass with substance | Physical property of Reactants | Beaker A | 66.97g | 68.22g including KI | White Powder | Beaker B | 65.91 g | 67.16 g including Pb(NO3)2 | Solid white crystals | Filter paper | 0.56g | 2.16g including PbI2 | Yellow Precipitate |

Post Lab Calculations 1. Ay=?
=Mass of the filter paper including substance – mass of filter paper with no substance = mass of
I have come to this conclusion based on three main facts that I found while researching. The first reason I found was that due of the amounts of ethanol that humans would need in order to keep up with the demand of our lifestyle. North America would need all crops to be specifically corn for ethanol production. This would lead to food prices sky rocketing. The second reason why this is not an efficient alternative is because its costs more than petroleum to produce. And the third reason why ethanol is not a useful alternative is because a new engine would need to be created so that it could run on pure ethanol. This is because as of now the majority of engines would not be able to run on the product of pure ethanol. There are also many negative effects that impact the environment, in regards to the production of ethanol. The first effect is that the reaction produces carbon dioxide which is a greenhouse gas that the world is trying to get rid of. The second negative effect is that shipping the corn around the world to be produced would require gas, which emits more bad chemicals into the world. It is for these reasons that I personally do not believe that ethanol is a worthwhile alternative to