Model IV:  H+ - NH4+ - Na+ - SO42− - NO3 - Cl - H2O

Parametrics:  variable inorganic chemical composition

Here, the ionic composition of the system is changed by substituting one cation or anion for another, over a specified range of amounts. A maximum of 100 points can be generated. Further information on the input and output quantities is given here.

First, choose the form of output required:

Normal       Column       Graph

Next, specify the problem in the input fields below.

Ambient Conditions

(1)  Temperature (180 - 330 K):   (See inputs for details of restrictions on the temperature range, related to the chemical composition of the system.)

(2)  The water content of the system must be specified as either a (fixed) ambient relative humidity, or the number of moles of total or water present per m3 of atmosphere. Select one:

   Relative humidity          Total water          Liquid water

Now enter the relative humidity (range 0.1 - 1.0) or moles of water present:

(3)  If the temperature is less than 273.15 K, and you wish the system to be equilibrated to the water vapour pressure over ice, then check the box here. (This option has no effect if total or liquid water has been selected above.)

Inorganic Composition in Moles per m3

(1)  Enter the initial composition of the system:

H+:      NH4+:     Na+:   NH3 (ammonia):
SO42:      NO3:     Cl:
Show Options:     Hide Options (and set to default values):

(2)  Select the ions whose amounts in the mixture are being changed. Note that they must both be either cations or anions. Also, the "initial" ion (which is being substituted for) must be present in a non-zero amount in the mixture above.

Initial ion: Substituting ion:

Now enter the range of substitution of the initial ion, in mole percent, followed by the number of points to be calculated:

Start value:      End value:      No. of points:

Other Chemical Components

The amounts of organic compounds present can be entered here. First, click the button to select compounds from the library or create new ones for this session.

Trace Gases

Check the boxes below to disable the partitioning of selected trace gases into the vapour phase. (The default for each gas is that partitioning is calculated.)

Prevent partitioning of the following gases:


Solid Phases

Check the boxes below to prevent the formation of selected solids, according to the restrictions that apply for this model. This enables the properties of metastable, supersaturated, aqueous aerosols to be investigated. The default for each calculation is that all solids can form.

No boxes should be checked for any systems containing both NH4+ and Cl ions.

Omit the following solids:

Ice H2SO4 · H2O H2SO4 · 2H2O
H2SO4 · 3H2O H2SO4 · 4H2O H2SO4 · 6.5H2O
HNO3 · H2O HNO3 · 2H2O HNO3 · 3H2O
HCl · 3H2O (NH4)2SO4 (NH4)3H(SO4)2
NH4HSO4 NH4NO3 2NH4NO3 · (NH4)2SO4
3NH4NO3 · (NH4)2SO4

To submit your calculation, click here: