What is the volume (in L) of 35.0 g of HBr gas at 715 torr and
90.0 oC?

Do you know the ideal gas formula?



You can find the number of moles of HBr present.
The formula here has units Pascal for pressure, metre cube for volume, moles for the number of moles, Kelvin for temperature and the constant is Joules per Kelvin per mole.

You have the pressure, the temperature and the moles now, and the constant is 8.31J/(K mol).