Hf is a corrosive gas. at 2.0 atm and 300 k, hf occupies a 4.50 l volume. how many grams of hf are in the volume? 1. 7.3 g 2. 2.74 g 3. not enough information is given. 4. 0.573 g 5. 15.6 g 6. 4.82 g

First we need to find the number of HF moles in the sample using the ideal gas law equation 
PV = nRT
P - pressure - 2.0 atm x 101 325 Pa/atm = 202 650 Pa
V - volume  - 4.50 x 10⁻³ m³
n  - number of moles 
R - universal gas constant - 8.314 Jmol⁻¹K⁻¹
T - temperature - 300 K
substituting these values in the equation
202 650 Pa x 4.50 x 10⁻³ m³ = n x 8.314 Jmol⁻¹K⁻¹ x 300 K
n = 0.366 mol

molar mass of HF = 20 g/mol
mass present - number of moles x molar mass = 0.366 mol x 20 g/mol = 7.32 g
answer is 1) 7.3 g