Evaporation of water and escaping particles

[tt2348]

Homework Statement

The heat of vaporization is approx the product of the average energy of the escaping molecules (E) and the # molecules per gram, N

I want to know, is this is as simple as it sounds

Homework Equations

so H=E*N?
Q=mH

The Attempt at a Solution

I'm supposed to find E, but I want to make sure I'm understanding it correctly

I get E=(H(v)*MW(h2o))/(N_a)=1.6111 x 10^-20 cal/molecule = 6.7452 x 10^-20 J/molecule
or 4.21 x10 eV/molecule

I can't find anything on average energy per molecule escaped, so i don't know how to confirm.

 

[mark726]

I would like to clarify and provide additional information on the concept of heat of vaporization and its relationship to the average energy of escaping molecules.

Firstly, the heat of vaporization (H) is defined as the amount of energy required to convert a substance from its liquid state to its gaseous state at a constant temperature. It is a measure of the strength of intermolecular forces in a liquid and is typically expressed in units of Joules per mole (J/mol).

Now, the average energy of escaping molecules (E) refers to the average kinetic energy of the molecules that are breaking away from the liquid surface to form a gas. This energy is directly related to the temperature of the liquid and can be calculated using the Boltzmann distribution equation: E= kT, where k is the Boltzmann constant and T is the temperature in Kelvin.

The number of molecules per gram (N) is also known as the Avogadro number (N_A) and is equal to 6.022 x 10^23 molecules/mol.

Therefore, the relationship between H, E, and N can be expressed as H=E*N, as stated in the forum post. However, it is important to note that this is an approximation and may not hold true for all substances. The actual value of H also depends on other factors such as pressure, temperature, and intermolecular interactions.

In conclusion, the concept of heat of vaporization and its relationship to the average energy of escaping molecules is a complex one and cannot be simplified to a single equation. it is important to consider all relevant factors and not rely solely on a single equation to understand a concept.