Non STP Problems

Congratulations You have successfully completed the non-STP problems tutorial

DirectionsUse the arrows at the bottom of the page to move forward and backward through the tutorial In the quiz click on the block to advanceMASS-Volume ProblemsMg(s) + O2(g) MgO(s) with 5g of Mg at STPFirst Step: Balance the equation2Mg(s) + O2(g) 2MgO(s) Second Step: Find the grams/mole of the solids (using the periodic table)2Mg(s) + O2(g) 2MgO(s) 24 g/m40 g/mThird Step: At STP the liters/mole is 22.42Mg(s) + O2(g) 2MgO(s) 24 g/m 22.4 L40 g/m

Mass-volume problems (cont)Fourth Step: Find moles by dividing the grams by the grams/mole 5g 2Mg(s) + O2(g) 2MgO(s) 24 g/m 22.4 L40 g/m0.208mFifth Step: Use the mole ratio to determine the moles of the other components 5g 2Mg(s) + O2(g) 2MgO(s) 24 g/m 22.4 L40 g/m0.208m 0.104m 0.208m

Mass-volume problems (cont)Sixth Step: Multiply the other moles by their grams/mol or liters/mol 5g 2.32L 8.32g 2Mg(s) + O2(g) 2MgO(s) 24 g/m 22.4 L/m40 g/m0.208m 0.104m 0.208m

Why do we use 22.4 l/m?To achieve the value of 22.4, you take any GAS find its molecular mass and multiply that number by 1 liter divided by the gass density. (located in the CRC handbook)Ideal Gas LawPV=nRTV/n= (RT)/PR = 8.31 (Constant)At STP Temp. = 273 K, Pressure = 101.325 KPAV/n = (8.31)(273K)/(101.325 KPA)V/n = 22.4 Liters/mole

Finding L/m at non-stpPv=nRTV/n = (RT)/(P)Find the Liters/mole if temp = 20 degrees C, and the pressure = 600 torrs1) convert temp. to kelvin and pressure to KPa20 C + 273 = 293 K600torr x (1/760) x (101.325/1) =80 KPa V/n = (8.31 x 293) / (80) V/n = 30.4 L/MFind mass-volume problem at non-stpRepeat the same steps as in the example shown for STPExcept instead of using 22.4 L/m to find the liters you find the liters/mole (V/n), using the equation on the previous side.

exampleFind the volume in Liters of oxygen and hydrogen when the pressure is at 167.97 Kpa and the temperature is 68 degrees C?18gH2O H2 + O2 18g 16.87l8.44l2H2O(L) 2H2(g) + O2(g) 18g/m16.87l/m 16.87l/m1m 1m 0.5m

exampleDo not forget to convert your unitsV/N = RT/PV/N = (8.31Kpa/mK)(341K)/(167.97KPa)Figure out the equationV/N= 16.87 liters/ 1 mole 18g 16.87l8.44l2H2O(L) 2H2(g) + O2(g) 18g/m16.87l/m 16.87l/m1m 1m 0.5m

QuestionsFirst Question:If the temperature is in Celsius degrees and the pressure is in torrs. Temperature has to be in Celsius.

FALSETRUEOops, sorry thats inncorrectBecause of the constant 8.31 Kpa/MoleKelvin, the temperature has to be in Kelvin and the pressure has to be in Kpa Back to question 1Oops, sorry thats inncorrectTo find Kpa from torrs divide by 760 and then multiply by 101.325

Go back to question 2Oops, sorry thats inncorrectV/n = (RT)/PRemember to convert temperature and pressure

Go back to question 3OOPS, Sorry Thats IncorrectDid you remember to convert everything?What about balance the equation?Go Back to Question 4Oops, sorry thats incorrectMake sure you convert everything necessaryUse the formula V/n = Rt/PGo Back to Question 5Works CitedAll work was provided by the notes taken in Mr. Wolfes class this year and in Chem 1.