The Henry's Law Constants Section contains four fields for the following properties:
The Abbreviations Dialog shows the definitions of all the abbreviations used in Cranium and Synapse. To activate the dialog, select the Help menu's Abbreviations command. See here for documentation.
The various Henry's Law Constants of a chemical 'i' in a solvent 's', are related to one another by the following equations:
where
| Mws | solvent molecular weight |
| T | system temperature |
| ρs | solvent density |
| P | system pressure |
| R | gas constant |
Each field contains a label, a datum control, an estimated value control, and a units control. The units control for two of the Henry's Law Constants are not active because those properties are dimensionless.
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1
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Datum Control: displays the field's physical property's data value. |
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2
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Estimate Control: displays the field's physical property's estimated value. |
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3
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Units Control: displays the current units for the field's physical property. Note that this field is displayed but inactive if the physical property is dimensionless. |
All the fields in this section contain numerical values. Thus, they all appear similar and are edited in the same manner.
The Data column of each field displays a physical property data value. The data value is displayed in the units shown in the Units column. A green triangle in the data control's upper right corner indicates that additional data are available. (See documentation on the Datum-Reference All Data Dialog and the Datum-Units-Reference All Data Dialog for details on managing data having different status.)
Clicking the left mouse button on a datum control activates a datum edit dialog enabling you to enter a value, accuracy, units, reference and comment.
If the field's property is dimensionless, the Datum-Reference Edit Dialog is activated. (See here for documentation.) If the field's property has units, the Datum-Units-Reference Edit Dialog is activated. (See here for documentation.)
Clicking the right mouse button within the field's datum control activates the field's datum commands menu.
The menu's commands enable you to copy, cut and paste values to and from the data control. See Common Menu Commands for documentation on the commands commonly found on command menus. See below for documentation on this field's specific menu commands.
Each property field runs a set of verification tests to check the validity of an entered value. Specifically, the value of a Henry's Law Constant must be greater than 0. Cranium or Synapse will signal an error if the entered value fails a physical property verification test.
The estimated value control of each field displays the physical property's estimated value. Unless the property is dimensionless, the value is displayed in the units shown in the field's Units control.
Clicking the left mouse button on an estimate control activates the Estimation Details dialog.
The Estimation Details dialog shows the estimated value, the technique used to generate the estimate, and any comments generated during the estimation. The dialog also has two buttons to provide more information about the technique used to generate the estimate:
Clicking the right mouse button on the estimate control displays the command menu.
The menu's commands enable you to copy values, clear values and manage the property's estimation techniques. See Common Menu Commands for documentation on the commands commonly found on command menus. See below for documentation on this field's specific menu commands.
The dialog lists two estimation modes: Automatic and Manual. By default all estimations are initially set to Automatic Mode. Once you choose Manual Mode, the list of estimation techniques is enabled allowing you to choose any estimation technique known to the application. See documentation on Manual Techniques Dialog for details about manually selecting estimation techniques.
Note that values cannot be pasted into a field's estimated value control.
The Units column of each field displays the units in which the data value and estimated value are displayed. (Note that only two Henry's Law Constants fields have active units control. The other two fields' units controls are not active because their associated physical properties are dimensionless.)
Clicking the left mouse button on the field's units control activates the Set Property Units dialog.
Selecting new units from the list and press the OK button changes the current units in which the property is displayed. (Note that all data are stored in their original units - changing the displayed units does not change any stored data.) The dialog's Std Units button displays the default units used by Cranium and Synapse for the current physical property. All estimated values are generated by Cranium and Synapse in standard units. (See documentation on the Property Units Dialog for additional details on changing property units.)
The units set via the Set Property Units dialog, accessed either from the Options menu's Set Units command or clicking on the Units control in a physical property field, are assigned for all documents in the application. For example, if you have three knowledge base documents open and then change the units of the water solubility, all documents will update their water solubility displays using the newly selected units.
Units are also stored in the application. The next time Cranium or Synapse starts, the set of units used in your last session will be used again.
| Topic | Description |
|---|---|
| Estimating Chemical Properties | a short video demonstrating how to estimate physical properties using either Synapse or Cranium. |
| Getting Started using Cranium | provides a quick tour of Cranium's capabilities including physical property estimation and a discussion of structure editing. |
| Chemicals Chapter | the chemicals chapter contains numerous sections for entering and displaying data and estimates including the chemical structure section. |