ALEKS, Philip Potapchuk xtOSppose A 500 ML Flask xrGchegg Chttps://www.awb.aleks

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ALEKS, Philip Potapchuk xtOSppose A 500 ML Flask xrGchegg Chttps://www.awb.aleks.com/alekscgi/x/isl.exe/1o u-IgNslkr7/8 Suppose A 500. ML Flask CChegg Study | Guided Sol Customer Servicex 1MX3p547r O ACIDS, BASES AND AQUEOUS EQUILBRIA h comsion of buferof ogpen ph A chemistry graduate student is given 125. ml of a 0.60 M methylamine (CH,NH,) solution. Methylamine is a weak base with K,-44 10 of CH3NH,CI should the student dissolve in the CH,NH2 solution to turn it into a buffer with pH -10.79 what mass of CH,NH,Cl should the student You may assume that the volume of the solution doesn't change when the CH3NH,CI is dissolved in it. Be sure your answer has a unit symbol, and round it to 2 significant digits. dissolve in the CH,NH2 solution to turn it into a buffer with pH-10.79 alo 1P Check

Explanation / Answer

POH   = PKb + log[CH3NH3Cl]/[CH3NH2]

PKb   = -logKb

        = -log4.4*10-4

       = 3.3565

POH = 14-PH

         = 14-10.79 = 3.21

no of moles of Ch3NH2 = molarity*volume in L

                                   = 0.6*0.125 = 0.075moles

POH   = PKb + log[CH3NH3Cl]/[CH3NH2]

3.21    = 3.3565 + log[CH3NH3Cl]/0.075

log[CH3NH3Cl]/0.075 = 3.21-3.3565

log[CH3NH3Cl]/0.075 = -0.1465

[CH3NH3Cl]/0.075     = 10-0.1465

[CH3NH3Cl]/0.075      = 0.7136

[CH3NH3Cl]               = 0.7136*0.076 = 0.05423 moles

mass of CH3NH3Cl   = no of moles *gram molar mass

                               = 0.05423*67.5 = 3.66g >>>> answer

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