We're asked to to find the mass of gaseous sulfur that occupies a volume of #2.45# #"L"# at standard ambient temperature and pressure.
I'll assume for these purposes that the sulfur is present as individual, gaseous atoms, rather than #"S"_8# (which is reasonable considering #"S"_8# is a solid at these conditions).
Standard ambient temperature and pressure (SATP) is defined as
We can use the ideal-gas equation to solve for the number of moles of sulfur, #n#, knowing that the gas constant, #R# is equal to #0.082057("L"•"atm")/("mol"•"K")#:
#PV = nRT#
#n = (PV)/(RT) = ((1cancel("atm"))(2.45cancel("L")))/((0.082057(cancel("L")•cancel("atm"))/("mol"•cancel("K")))(298.15cancel("K")))#
#= color(red)(0.100# #color(red)("mol S"#
Now, let's use the molar mass of sulfur, #32.07# #"g/mol"#, to calculate the number of grams:
#0.100cancel("mol S")((32.07color(white)(l)"g S")/(1cancel("mol S"))) = color(blue)(3.21# #color(blue)("g S"#
Thus, if a #2.45#-#"L"# tank is filled with pure gaseous sulfur at SATP, we can expect the sulfur sample to have a mass of #color(blue)(3.21# #sfcolor(blue)("grams"#.