Recitation session seven

# Recitation session seven - temperature What is the white...

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Recitation session seven Question 1 John dissolves an 1.25 gram aliquot of limestone in an acid solution. He does that in a vessel that is attached to a cylinder that traps the carbon dioxide gas that is evolved. He finds that 290 mL of gas is evolved. Limestone is mostly calcium carbonate but can contain some silicates or quartz that does not react with the acid. What percentage of the limestone is (calcium) carbonate? The temperature is a balmy 30 o C as John lives in Florida and the pressure is 1 Atm Question 2 Mary studies a mixture of helium and argon of one liter at room temperature (25 o C) at 1atm pressure in a cylinder. She brings the cylinder in contact with a pool of liquid nitrogen (77K) at which point a small amount of a white substance deposits on the walls of the cylinder and the volume of the gas reduces to 227 ml. Neglecting the volume of the solid formed, what was the partial pressure of the helium at room
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Unformatted text preview: temperature? What is the white powder? Boiling point of helium: 4.2K; of argon -185.7 o C. Melting point of argon -183 o C Question 3 Air+HCl(g) Air +NH3(g) Two sturdy compartments of 1 cubic meter each are filled with gas mixtures and separated by a thin wall. On the left is air containing a concentration of 0.5 [mol/L] of HCl gas. On the right is air with 0.25 [mol/L] ammonia gas. Both compartments are are 25oC and 1 atmosphere total pressure. The thin wall is punctured and a white fog of solid ammonium chloride is formed that slowly precipitates into a thin dust of the floor of the containers. How many moles and grams of HCl are in the left compartment before the wall is punctured? What is the final pressure of the gas in the container? What is the limiting reactant? What is the mass of the solid ammonium chloride formed?...
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## This note was uploaded on 11/08/2011 for the course CH 101 taught by Professor Bigham during the Spring '08 term at N.C. State.

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