Question

In a `72.9*g` mass of manganese metal, what molar quantity is present with respect to the metal?

Answer 1

Approx. `1.3*mol`.....

Explanation:

`"Number of moles"-="Mass of stuff"/"Molar mass of stuff"`

`=` `(72.9*g)/(54.9*g*mol^-1)=??*mol`

Remember what the mole is, viz. simply a (LARGE) number.....

`1*mol-=6.022xx10^23*"individual particles"`, with the property that `1*mol` of `""^1H*"atoms"` has a mass of `1*g`. The mole is thus the link between the micro world of atoms and molecules, of which chemists CONCEIVE, to the macro world of grams, and litres, that which chemists MEASURE on a laboratory bench. It is worthwhile spending some time on this notion.

How did I know the molar mass of manganese? Did I have it memorized?