Entering Formulas

Once the program starts, you may enter a molecule's formula on the numbered line. Calculate the weight of a formula by pressing the ENTER key or clicking the Calculate button. In Multi View mode, this will create a new blank line for a new formula (unless the Advance on Calculate option is set to No). This is useful for comparing molecular weights of multiple compounds. The maximum number of formulas to show is adjustable, allowing you to prevent the window from growing to fill the screen.

Move among the lines using the UP and DOWN arrow keys or the TAB and SHIFT-TAB keys. Pressing ENTER on line 'n' when line 'n+1' already has a formula will simply move the cursor to line n+1. A formula can consist of elements, element subscripts, parentheses, dashes (-) for hydrates followed by numbers to separate parts of a compound (NOT subtract them), and brackets for weighting parts of a compound.

The Element Mode Quick Switch can be used to quickly change the element mode between average, isotopic, and integer modes.

See the examples for a wide variety of example formulas.

NOTE: For Radioactive elements, the most stable isotope is NOT used; Instead, an average Molecular Weight is used, just like with other elements. See the isotopes section for the method of indicating an isotopic mass. Data originally obtained from the Perma-Chart Science Series Chemical Periodic Table, 1993; ISBN 1-55080-063-9, then updated using the 1997 IUPAC standard atomic weights and uncertainties found in Pure Appl. Chem., 68, 2339-2359 (1996); 69, 2471-2473 (1997).

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