1. A quantity of molecular hydrogen (H2) gas fills a one liter container at a temperature of 200 K and pressure of 1 atm. What is the average (rms) speed of the molecules? 2. Relevant equations KE_trans = 1/2 M<v^2> Energy_trans = 3/2kT = 3/2RT H2 = 2g/mol 3. The attempt at a solution Assuming 1 mol of H2: mass = .002kg 1/2 M<v^2> = 3/2RT (.002kg)<v^2> = 3R(200K) <v^2> = 2494200m/s Vrms = sqrt(<v^2>) = 1579.30m/s Which is wrong. The correct answer is 1600m/s. (Not a rounding error.) Can anyone help me? Thanks!