Home
Common Compounds
Exam Guide
FAQ
Features
Glossary
Companion Notes
Just Ask Antoine!
Resources
Slide Index
Toolbox
Tutorial Index
FAQ
Introduction
Measurement
Matter
Atoms & ions
Compounds
Chemical change
| The mole |
Energy & change
The quantum theory
Electrons in atoms
The periodic table
Chemical bonds
Solids
Liquids
Solutions
Acids & bases
Redox reactions
Reaction rates
Organic chemistry
Everyday chemistry
Inorganic chemistry
Environmental chemistry
Laboratory
History of chemistry
Miscellaneous
Home  FAQ The mole concept | Print | Comment | Contact |
| Previous Question | Next Question |
How can I find molecular weights for specific substances?
- Can you tell me the molecular weights of KHP and aspirin?
totoybato1@hotmail.com -
First, you must look up the molecular formula for the compounds. The molecular formula of KHP (potassium hydrogen pthalate) is C8H5O4K, and the molecular formula of aspirin (acetylsalicylic acid) is C9H8O4.
The sum of atomic weights in the formula gives you the compound's molecular weight:
KHP, KC8H5O4 aspirin, C9H8O4 8 carbons 8×12.011 = 96.088 9 carbons 9×12.011 = 108.099 5 hydrogens 5×1.00797 = 5.03985 8 hydrogens 8×1.00797 = 8.06376 4 oxygens 4×15.9994 = 63.9976 4 oxygens 4×15.9994 = 63.9976 1 potassium 1×39.102 = 39.102 sum: 180.160 sum: 204.227
newsletter describing updates,
new features, and changes
on this site.
General Chemistry Online! How can I find molecular weights for specific substances?
Copyright © 1997-2001 by Fred Senese
Comments & questions to senese@antoine.frostburg.edu
Last Revised 02/23/18.URL: http://antoine.frostburg.edu/chem/senese/101-hidden/moles/faq/molecular-weight.shtml