# Example problem deep sea divers use special gas

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Example Problem: Deep sea divers use special gas mixtures in their tanks. Atypical gas cylinder contains 51.2 g of O2and 326.4 g of He and has a totalpressure of 200. atm. Calculate the partial pressure of each gas.
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Chem 1035 Chapter 5 33 of 46Diffusion and EffusionDiffusion: movement of one gas through another, gases mix spontaneously (perfume)Effusion: movement of gas particles through a pinholeVelocity is dependent on molar mass and temperatureGases of different molar masses at the same temperature move at differentvelocities Vacuum
Chem 1035 Chapter 5 34 of 46KE = ½mv2Heavier gas moves slowly
Chem 1035 Chapter 5 35 of 46The Relationship Between Molar Mass and Molecular Speedheavier gas – slower speed
Chem 1035 Chapter 5 36 of 46Graham's Law:
Example Problem: How much faster will a sample of Ne (20.2 g/mol) effuse than a sample of Cl2(70.9 g/mol) at a particular temperature?
Chem 1035 Chapter 5 37 of 46Example Problem: Neon effuses 1.26 times as fast an an unknown gas at a particular temperature. What is the molar mass of the unknown gas?
Chem 1035 Chapter 5 38 of 46Real GasesIdeal Gas: gas that obeys the ideal gas law and kinetic molecular theory, all assumptions are trueReal Gas: all assumptions are not always true
Chem 1035 Chapter 5 39 of 46
Chem 1035 Chapter 5 40 of 46Two assumptions for ideal gases that don't hold true for real gases:1. Volume of gas particles does not equal 0Small but measurable (must adjust volume down)2. Gas particles do have attractive and repulsive forces between particles (mustadjust pressure up) Modify the Ideal Gas Equation to correct for these deviations:van der Waals equation:a: correction factor for attractive forcesb: correction factor for volumeP+ an2V2V - nb= nRT
Chem 1035 Chapter 5 41 of 46
Chem 1035 Chapter 5 42 of 46