Group+A

The Question: A 0.550 g sample of solid lead (II) nitrate is added to 250 mL of 0.100 M potassium iodide.
 * (a) Write a balanced net ionic equation.
 * (b) Identify the oxidation numbers for each species involved in the equation from (a).
 * (c) Identify the oxidizing and reducing agents. Justify your choice.
 * (d) Calculate the number of moles of each reactant.
 * (e) Identify the limiting reactant. Show calculations to support your identification.
 * (f) Calculate the molar concentration of NO3﻿ - (aq). in the mixture after the reaction is complete.
 * (g) Create a diagram that accurately depicts the contents of the reaction after the reaction is complete.



Group_A_Answer_Key.jpg

The Authors: Daniel Sottile and Konrad Thaler **Due Date**: Friday 8th, October. __ <span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 110%;"> The Question: A 0.550 g sample of solid lead (II) nitrate is added to 250 mL of 0.100 M potassium iodide. Pb(NO3­­­)2 (aq) + 2KI (aq) = 2K(NO3) (aq) + PbI2 (s) Balanced Chemical Equation Pb+(aq) + (NO3­­­)2- (aq) + 2K+(aq) + 2I- (aq) = 2K+(aq) + 2NO3- (aq) + PbI2 (s) Pb+(aq) + 2I- (aq) = PbI2 (s) Balanced Net Ionic Equation Pb+(aq) + 2I- (aq) = PbI2 (s) +2 -1 +2 -1 Pb (II): Begins at +2 and remains at +2 after the reaction, therefore, no oxidation or reduction occurred in this reaction. I: Begins at -1 and remains at -1 after the reaction, therefore, no oxidation or reduction occurred in this reaction. Take the mass in grams of Lead II Nitrate and divide it by its molar mass to get the number of moles: =1.66 X 10^-3 mol Pb(NO3)2 Take the amount of volume in liters and multiply it by the molarity to get the amount of moles of Potassium Iodide: =2.50 X 10^-2 mol KI
 * (a) Write a balanced net ionic equation.
 * (b) Identify the oxidation numbers for each species involved in the equation from
 * (c) Identify the oxidizing and reducing agents. Justify your choice.
 * (d) Calculate the number of moles of each reactant.
 * .550 g Pb(NO3)2 || 1 mol ||
 * || 331.2 g ||
 * 250 mL || 1 L || .100 M KI ||
 * || 1000 mL ||  ||
 * (e) Identify the limiting reactant. Show calculations to support your identification.

Use the amount of moles for the reactant and mole ratios of it and the product to determine how many moles are produced. Then the lowest number is the limiting reagent. =.002 mol K(NO3) (Pb(NO3)2 is limiting reactant) =.025 mol K(NO3) Though throughout the reaction, (NO3)- does not change (spectator), so it is still aqueous, therefore, it all remains in the solution. There are 1.66 x 10^-3 mol of Pb(NO3)2, and use this number with the mole to mole ratio of NO3- to Pb(NO3)2 to find the number of moles of NO3-. Use this number and divide it by the volume of the solution to find the molar concentration of NO3- (aq) in the mixture. =1.33 X 10^-2 M (NO3)- (aq)
 * .001 mol Pb(NO3)2 || 2 mol K(NO3) ||
 * || 1 mol Pb(NO3)2 ||
 * .025 mol KI || 2 mol K(NO3) ||
 * || 2 mol KI ||
 * (f) Calculate the molar concentration of NO3- (aq). in the mixture after the reaction is complete.
 * 1.66 X 10^-3 mol Pb(NO3)2 || 2 mol (NO3)- || 1 M (NO3)- ||
 * || 1 mol Pb(NO3)2 || .250 L Solution ||

<span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 110%;">(g) Create a diagram that accurately depicts the contents of the reaction after the reaction is complete. (top is before, bottom is after) From Wikipedia //Lead (II) Nitrate most commonly occurs as a colorless crystal and is soluble in water. This compound has been known since the Middle Ages. In 1597, the German alchemist Adreas Libavius first described the compound, coining the medieval names of plumb dulcis and calx plumb dulcis, meaning "sweet lead", because of its taste.// //Historic uses of it include use in match head production, special explosives, and as the raw material in the creation of colors within lead based paints. Modern uses include heat stabilization in nylon and polyesters, and in coatings of photothermographic paper. This is a toxic, oxidizing agent. To produce Lead (II) Nitrate, dissolve lead in nitric acid and harvest the precipitate. (1)//



//Potassium Iodide most commonly occurs as a white salt, and is less hygroscopic than other salts, making it easier to work with. Aged samples are yellow due to the oxidation of the compound. It is typically used in medicinal tablets. It was previously used as a disinfectant and in developing photographs. (2)//



(3) ­­­­­­ media type="youtube" key="DITY2rXYU-I?fs=1" height="385" width="480"

Works Cited:

(1) "Lead(II) Nitrate." //Wikipedia, the Free Encyclopedia//. Web. 08 Oct. 2010. <http://en.wikipedia.org/wiki/Lead(II)_nitrate>.

(2) "Potassium Iodide." //Wikipedia, the Free Encyclopedia//. Web. 08 Oct. 2010. <http://en.wikipedia.org/wiki/Potassium_iodide>.

(3) "Reaction of Lead Nitrate & Potassium Iodide Solution." //Youtube//. Web. 08 Oct. 2010. <http://www.youtube.com/v/DITY2rXYU-I?fs=1>.