showed that atmospheric particles containing soluble salts also
contain a substantial amount of water which varies with the relative
humidity. In this
lesson we explore the conditions under which these particles are completely
solid, and the transition from solid to liquid state.
Before starting, ensure that this browser window occupies only the
left half of your screen. You should leave enough
space for another browser window where you can
enter data into E-AIM
and read the results. If your screen is too small for
two windows, print out this tutorial and use this window to enter data and
's results. In these lessons we assume that you will
have two browser windows open.
link to open a second browser window containing the data
input page for "simple" calculations using Model III
the windows on your screen so that both are visible and the left window
contains this text.
This consists of the three sets of calculations described in the links below,
which should be done in the order listed.
You have completed Lesson 2, and learned that:
- For a solid composed of volatile components, such as NH4NO3,
there is an equilibrium between the solid and the partial pressure
product of the components. This product is a function of temperature
- The phase state of a particle (i.e., solid or liquid) is a function of
the relative humidity.
- There is a transition between solid and liquid
state at a single relative humidity. This is known as the deliquescence point.
For a single salt it varies only with temperature.
At relative humidities below the deliquescence point,
the particles are solid whereas above it they are fully liquid. We
have only examined a single solid here (NH4NO3).
However, the deliquescence point varies widely for different salts.
- The concentration of an aqueous solution of a salt at the deliquescence
point is the same as the solubility of the salt.
Now proceed to Lesson 3
to explore how solid phases
form in aqueous aerosols under different conditions.