Question

Find the rms speed of hydrogen (H2) at 273 K. How much does the rms speed change when the temperature goes to 500 K?

Answer 1

Mass of H2 is m = 2x1.67x10 ^-27 kg

Tempearture T = 273 K

Rms speed v = [3kT/m]

Where k = Boltzmann constant = 1.38 x10 ^-23 m² kg s^-2 K^-1

Substitute values you get ,

   v = [(3x1.38 x10 ^-23x273) / (2x1.67 x10 ^-27 )]

      = 1839.5 m/s

Mass of H2 is m = 2x1.67x10 ^-27 kg

Tempearture T ' = 500 K

Rms speed v ' = [3kT ' /m]

Where k = Boltzmann constant = 1.38 x10 ^-23 m² kg s^-2 K^-1

Substitute values you get ,

   v ' = [(3x1.38 x10 ^-23x500) / (2x1.67 x10 ^-27 )]

      = 2489.5 m/s

Change in rms speed = v ' - v = 2489.5 m/s - 1839.5 m/s

                                = 650 m/s