MathBench > Measurement

Calculating Molar Weight

What is a mole?

No, but moles are fascinating animals — they eat 50% of their weight in worms daily and scent-mark their tunnels continually to protect their architectural investments.


No, this is chicken mole. Yummy, but no cigar.

Yes, these bars each represent 1 mole of a particular metal — copper, iron, zinc, or aluminum.


To be a little more exact, a mol is approximately 6.022 x 1023 atoms or molecules. A mol is not a measure of WEIGHT — rather, it is a measure of NUMBER. Kind of like a dozen. So,

1 dozen = 12 of something

1 mol = 602,200,000,000,000,000,000,000 of something

We interrupt this module for an IMPORTANT NOTE: If at this point you are saying "Why do I have to do this? I've been calculating molar weight since middle school!" then please feel free to skip to the last page and do the 5 review problems there. If you can do them, then you don't need the module, and you can just take the quiz.