If you’re not aware, Organic Syntheses, a classic publication familiar to most organic chemists is available free online. Visit www.orgsyn.org/.
Of additional interest to chemists are several internet sites with free molecular mass calculation programmes. No need to use your calculator again! Try the following:
www.webqc.org/mmcalc.php
www.lenntech.com/calculators/molecular-weight-calculator.htm



A good site to help calculate molecular properties and drug-likeness of any molecule visit:

www.molinspiration.com/cgi-bin/properties



If you know of any other or better free sites please let me know and I’ll circulate them.