You may have experienced that wet cloth dries and water in the glass evaporates at room temperature. Now, we are going to calculate how fast the water in a cup is evaporating using the Maxwell-Boltzmann equation. We need to provide 40,660 Joules for one mole (~6 x 1023 molecules or 18 grams) of water to evaporate at room temperature. One mole of water is contained in a wide and shallow cylinder. The number of water molecules exposed to the air on the water surface is 5 x 1018. How much energy is needed for a single water molecule to evaporate (liquid phase turning to gas phase)? Calculate the probability of water molecule at the surface of water escape to air by its random vibration motion. If the molecules on the surface vibrates at frequency of 3 x 107 Hertz, how many molecules are escaping from the water surface for one second. Assuming water molecules in the air do not condensate (do not return back to water) because they are efficiently removed away by a mild wind, calculate the time for 18 gram of water evaporate completely.

You may have experienced that wet cloth dries and water in the glass evaporates at room temperature. Now, we are going to calculate how fast the water in a cup is evaporating using the Maxwell-Boltzmann equation. We need to provide 40,660 Joules for one mole (~6 x 1023 molecules or 18 grams) of water to evaporate at room temperature. One mole of water is contained in a wide and shallow cylinder. The number of water molecules exposed to the air on the water surface is 5 x 1018. How much energy is needed for a single water molecule to evaporate (liquid phase turning to gas phase)? Calculate the probability of water molecule at the surface of water escape to air by its random vibration motion. If the molecules on the surface vibrates at frequency of 3 x 107 Hertz, how many molecules are escaping from the water surface for one second. Assuming water molecules in the air do not condensate (do not return back to water) because they are efficiently removed away by a mild wind, calculate the time for 18 gram of water evaporate completely.