This page permits practice with the relationships between mass, moles and the
gram formula weight (GFW or molar mass).
When you press "New Problem", values will appear in two of the windows. Enter
missing value and press "Check Answer". The results will appear in the second
table. Redo any problems you get incorrect and resubmit the new results. You can press "New Problem" rather than answer the one displayed. Pressing "Show Answer" will cause the correct answer to appear and you will no longer be able to submit an answer for that problem.