Place your cursor in the field at the top-left (it should be automatically there).
Type a Chemical Formula, using only normal brackets (meaning '(' and ')'
Chemical composition and elemental analysis will be shown as you type
* For some reason I can't get other types of brackets to work, but
given the tool tells you of a mistyped formula, you should not have
for each conversion, please alter the type of units as needed before converting
Converting mass to mmol
Enter a mass in the mass field, and click the arrow with the yellow box on it to get the mmol
Converting volume to mmol (no mass needed)
Enter a volume in the volume field, and a density, and click the arrow with the blue droplet on it to get the mmol
Converting mmol to volume/mass
Fill in the density field (if needed), and enter the value of mol/mmol. conversion is automatic
They appear in a box like below, and describe the error. Two exist; one
saying that the element is unknown (a mistype or use of shorthand),
and the other saying your brackets are mismatched