Question

Chapter 8

Problem 8.113 - Clinical Applications

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Constants | Periodic Table A gas mixture with a total pressure of 2500 torr is used by a scuba diver. If the mixture contains 1.5 moles of helium and 7.0 moles of oxygen, what is the partial pressure, in torr, of each gas in the sample?	Part A PHe = _____ Express your answer in torr to two significant figures. nothing   torr   SubmitRequest Answer Part B PO2 = _____ Express your answer in torr to two significant figures. nothing   torr   SubmitRequest Answer Provide Feedback Next

Answer 1

no of moles of He (nHe) = 1.5 moles
no of moles of O2(nO2)   = 7 moles
Total no of moles of He and O2 ( nHe + nO2) = 1.5 + 7 = 8.5 moles
mole fraction of He ( XHe) = nHe/nHe + nO2
                            = 1.5/1.5 +7
                            = 1.5/8.5   = 0.1765
mole fraction of O2 ( XO2) = nO2/nHe + nO2
                            = 7/1.5 +7
                             = 7/8.5    = 0.8235
Total pressure of mixture (PT) = 2500 torr
partial pressure of He ( PHe)   = XHe * PT
                                = 0.1765*2500   = 441.25 torr
partial pressure of O2 ( PO2)   = XO2 * PT
                                = 0.8235*2500 = 2058.75 torr