A gas, collected by water displacement, occupies 781781 cm^3cm3 at 14°C and 99.1 kPa. What volume will the dry gas occupy at STP?

1 Answer
Jun 22, 2018

The question is INCOMPLETE...we need P_"saturated vapour pressure" at 14 ""^@C...we also need to specify "STP"...

Explanation:

P_"SVP"=12.0*mm*Hg at 14 ""^@C

Now the quoted pressure is …….

(99.1*kPa)/(101.3*kPa*atm^-1)xx760*mm*Hg*atm^-1=743.5*mm*Hg

And P_"Total"=P_"SVP"+P_"gas"

P_"gas"=P_"Total"-P_"SVP"=(743.5-12.0)*mm*Hg=731.5*mm*Hg

And "STP" specifies a pressure of 0.987*atm-=750.2*mm*Hg, and T-=273.15*K

That out of the way...(P_1V_1)/T_1-=(P_2V_2)/T_2

We solve for V_2=(P_1V_1)/T_1xxT_2/P_2

(743.5*mm*Hgxx781*cm^3)/(287*K)xx(273.15*K)/(750.2*mm*Hg)

=736.6*cm^3...