Given a gas under #600"mm Hg"# pressure, and at #303.15K# temperature, that occupies a volume of #2.02L#, what volume will it occupy at #273.15K# temperature, under #750*"mm Hg"# pressure?

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Answer 1 · 2017-08-02T08:27:41

Well, the current definition of #"STP"# is.... a temperature of #273.15*K# and a pressure of exactly #10^5*Pa# #(100*kPa, 1*"bar")#.

And #1*"bar"-=(1*"bar")/(1.01325*atm*"bar"^-1)=0.987*atm#

I do all this rigmarole BECAUSE I know that #1*atm# will support a column of mercury that is #760*mm# high...........

And hence in terms of the length of a mercury column, #1*"bar"-=760*mm*Hg*atm^-1xx0.987*atm=750.0*mm*Hg#

#(P_1V_1)/T_1=(P_2V_2)/T_2#

We want #V_2=(P_1V_1)/T_1xxT_2/P_2#

#(600.0*mm*Hgxx2.02*L)/(303.15*K)xx(273.15*K)/(750*mm*Hg)#

#~=1.5*L#

Given a gas under #600*"mm Hg"# pressure, and at #303.15*K# temperature, that occupies a volume of #2.02*L#, what volume will it occupy at #273.15*K# temperature, under #750*"mm Hg"# pressure?