we can use the ideal gas law equation to find the number of Cl moles in the container PV = nRT where P - pressure - 1.1 atm x 101 325 Pa/atm = 111 458 Pa V - 17.8 x 10⁻³ m³ n - number of moles R - universal gas constant 8.314 Jmol⁻¹K⁻¹ T - temperature in Kelvin - 273 + 29 °C = 302 K substituting these values in the equation 111 458 Pa x 17.8 x 10⁻³ m³ = n x 8.314 Jmol⁻¹K⁻¹ x 302 K n = 0.790 mol molar mass of Cl₂ = 71 g/mol therefore mass of Cl₂ = 0.790 mol x 71 g/mol = 56.1 g mass of Cl₂ present - 56.1 g
