# assuming water molecules

• August 16th 2006, 10:33 AM
Celia
assuming water molecules
assuming water molecules in the gas phase act as an ideal gas, how many times greater is the rms speed of water molecules in the gas phase at the bolling temperature of water compared to the freezing temperature of water.
• August 16th 2006, 12:42 PM
CaptainBlack
Quote:

Originally Posted by Celia
assuming water molecules in the gas phase act as an ideal gas, how many times greater is the rms speed of water molecules in the gas phase at the bolling temperature of water compared to the freezing temperature of water.

The temperature (absolute) is proportional to the average translational KE
of the molecules. Therefore the absolute temperature is proportional to the
mean square speed of the water molecules, so

$
\frac{373}{273}=\frac{v_{T=100,\ rms }^2}{v_{T=0,\ rms}^2}
$
,

from which the ratio of the rms speeds can be found.

RonL