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Gases and Stoichiometry. Review Ideal Gas Law Gas Law Stoichiometry. Ideal Gas Law. Remember, mathematically, PV=nRT Where R = 8.31 LkPa/molK. Pressure x vol. = # of moles x ideal gas constant x temp. Ideal Gas Law.
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Gases and Stoichiometry Review Ideal Gas Law Gas Law Stoichiometry
Ideal Gas Law • Remember, mathematically, PV=nRT • Where 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.
Practice Problem • What volume will 12 grams of oxygen gas (O2) will occupy at 25oC and 52.7 kPa?
Practice Problem • How many grams of carbon dioxide can be contained in a 17.8L container at 22oC and 188kPa?
Gas Stoichiometry • Remember when we looked at chemical quantities and said that for any gas, 1 mole = 22.4L @ 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.
Practice Problem • In the reaction KClO3 KCl + O2 38.5g 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 (CH4), the carbon dioxide produced is trapped in a 31.3L container at 31oC. What is the pressure due to carbon dioxide in this container? (remember to write a balanced equation)
Molarity Review • 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.
Practice Problem • What is the molarity of a solution made by adding 38.77g MgSO4 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?