Mole Calculations

Definitions

One mole is equal to 6.02×10²³ things (things being N; particles, molecules, ions, ect.)

6.02×10²³ is called Avogadro's number (N_A or avo)

The number of mols of a substance is represented by n

The molar mass of a substance is the mass (m) of one mol (6.02×10²³ things) in grams

    (eg. Carbon has a molar mass of \frac{12.01g}{mol} , so one mole of Carbon has a mass of 12.01g     (and two moles has a mass of 24.02g))

Formula 1 (to find n & N)

This base formula can be rearranged to find the amount of things or moles in or of a substance:

N_{A}=\frac{N}{n}

where N_A = 6.02×10²³,

            N = things,

            n = # of moles

Formula 2 (to find n, m & M)

This base formula can be rearranged to find the amount of moles, the mass, or the molar mass of an substance:

n=\frac{m}{M}

where n = # of moles,

            m = mass (g),

            M = molar mass (\frac{g}{mol} )