Part 1 (non-ideal behavior ): we will use Van der Waals formula: P = (nRT/(V-nb)) - (n^2 a/V2) when n (moles of H2) = 18 g / 2 = 9 moles R (constant) = 0.0821 T(tempreature in kelvin = 20 +273 = 293 K V(Volume) = 1 L a (constant for H2) = 0.2476 b(constant for H2) = 0.02661 So by substitution: ∴P = (9*0.0821*293/(1-(9*0.02661))) - (9^2*0.2476/1) ∴P ≈264.6 atm
Part 2 (ideal behavior): we will use the ideal gas formula : PV = nRT when we have n = 9 R= 0.0821 T=293 K V= 1 L ∴P = (9*0.0821*293)/1 L ∴P = 216.5 atm