Calculate the volume at s.t.p. occupied by a gas 'Q' originally occupying 153.7cc at 287K and 750mm pressure [vapor pressure

of gas 'Q'at 287K is 12mm of Hg]

1 answer

I understand the question but not the parenthetical part.
Ignoring the part in parentheses, use (P1V1/T1) = (P2V2/T2)

note: I understand vapor pressure to be the pressure of the gas above and in equilibrium with a liquid. If gas Q has a pressure of 750 mm Hg at 287 K I don't understand how it can have a pressure of 12 mm Hg at 287 K.