text: You can try find and download "ChemBuddy-CASC" at the net. i forgot what the web address, but it's not hard to find just google it.\nfor the free version there's only some substances, but Hydrochloric Acid (if that what you mean) is one of them.\nThat program is very easy to use. just input the % wt then the SG/density will automaticaly come out.\n\nOther option : you can try find it at "Perry's - Chemical Engineer's Handbook"