How can you tell if a web site is trustworthy or not? It's not always easy, but there are things that you can look for that will help you decide.
Guide:
Government websites can often provide reliable information for chemistry. Here are a few:
www.usa.gov (Portal for the U.S. federal government)
www.cdc.gov (Centers for Disease Control and Prevention)
www.energy.gov (Department of Energy)
www.epa.gov (Environmental Protection Agency)
www.fda.gov (Food and Drug Administration)
www.nih.gov (National Institutes of Health)
webbook.nist.gov/chemistry (NIST Chemistry WebBook)
toxnet.nlm.nih.gov (TOXNET)
Here are some additional websites to consider:
WebElements
www.webelements.com
A periodic table with basic information on the elements.
Chemicool Periodic Table
www.chemicool.com
Includes a Chemistry Dictionary, Chemistry Tools, Resources, and a discussion and help Forum.
Molecular Weight Calculator
www.chemie.fu-berlin.de/cgi-bin/molform
Calculates molecular weights from molecular formulas.
ChemSpider
www.chemspider.com
This astonishingly powerful, award-winning database from The Royal Society of Chemistry provides fast access to over 30 million chemical structures and properties, as well as nearly unlimited links and related information.