Gases and Stoichiometry Review Ideal Gas Law Gas Law Stoichiometry

Ideal Gas Law Remember, mathematically,Remember, mathematically,PV=nRT Where R = 8.31 LkPa/molKWhere R = 8.31 LkPa/molK Pressure x vol. = # of moles x ideal gas constant x temp.

Ideal Gas Law Now that we have talked more exhaustively about the subject of moles as it relates to mass, we can add a new type of problem.Now that we have talked more exhaustively about the subject of moles as it relates to mass, we can add a new type of problem.

Practice Problem What volume will 12 grams of oxygen gas (O 2 ) will occupy at 25 o C and 52.7 kPa?What volume will 12 grams of oxygen gas (O 2 ) will occupy at 25 o C and 52.7 kPa?

Practice Problem How many grams of carbon dioxide can be contained in a 17.8L container at 22 o C and 188kPa?How many grams of carbon dioxide can be contained in a 17.8L container at 22 o C and 188kPa?

Gas Stoichiometry Remember when we looked at chemical quantities and said that for any gas, 1 mole = STP? Now we know that if you change the temperature and pressure, the relationship doesn’t work!

Gas Law Stoichiometry If gases are being produced or consumed in a chemical reaction, we can use stoichiometry along with the ideal gas law to solve problems for gases NOT at standard temperature and pressure.If gases are being produced or consumed in a chemical reaction, we can use stoichiometry along with the ideal gas law to solve problems for gases NOT at standard temperature and pressure.

Practice Problem In the reaction KClO 3  KCl + O g of potassium chlorate are burned and the resultant oxygen is captured at 100.7kPa and 298K. What volume of oxygen is generated?In the reaction KClO 3  KCl + O g of potassium chlorate are burned and the resultant oxygen is captured at 100.7kPa and 298K. What volume of oxygen is generated?

Practice Problem In the combustion of 25.3g methane (CH 4 ), the carbon dioxide produced is trapped in a 31.3L container at 31 o C. What is the pressure due to carbon dioxide in this container? (remember to write a balanced equation)In the combustion of 25.3g methane (CH 4 ), the carbon dioxide produced is trapped in a 31.3L container at 31 o C. What is the pressure due to carbon dioxide in this container? (remember to write a balanced equation)

Collecting Gas Over Water A common theme for many questions is collecting gas over water. Liquids have a pressure because of the particles that have evaporated just on top of the surface. To find out about “dry gas”—gas with no water vapor, use Dalton’s law to subtract it out.

Practice Problem Hydrogen gas and zinc sulfate is produced when zinc reacts with sulfuric acid. If 124 mL of wet H 2 gas is collected over water at 24 o C and a barometric pressure of 725 mm Hg, how many grams of Zn have been consumed? (the vapor pressure of water at 24 degrees C is mm Hg).

Molarity Review Remember, molarity is the SI measure of concentration, found by taking the number of moles solute per liter of solution.Remember, molarity is the SI measure of concentration, found by taking the number of moles solute per liter of solution. M = (mol solute)/(L solution)

Now that we have talked more exhaustively about the subject of moles as it relates to mass, we can use it with concentration.Now that we have talked more exhaustively about the subject of moles as it relates to mass, we can use it with concentration.

Practice Problem What is the molarity of a solution made by adding 38.77g MgSO 4 to enough water to make 0.85L solution?What is the molarity of a solution made by adding 38.77g MgSO 4 to enough water to make 0.85L solution?

Practice Problem How many grams of sodium nitrate are needed to make 500mL of 2.0M solution?How many grams of sodium nitrate are needed to make 500mL of 2.0M solution?