Question

What molar quantity is associated with `123*mg` of zinc metal?

Answer 1

Approximately 0.0000188 mol.

Explanation:

The equation for mol is
n= m `-:` M

'n' represents the number of moles (mol), 'm' represents mass (g) and 'M' represents molar mass of an element.

In this case, 'm' is 0.00123 grams and 'M' is the molar mass of zinc, which is 65.38.

So we simply divide the mass by the molar mass, and we get 0.00001881309269 mol, which is 0.0000188 when we consider significant figures.

Side note:

Another useful equation is n= N `-:` AC

Where 'n' still represents number of moles, but 'N' represents number of particles/atoms and 'AC' represents Avogadro's Constant, which is always 6.022 x `10^23`