Calculate the mass of 6.45 x 10^22 atoms of carbon

m (C) = ?

N (C) = 6,45*10²²atom

N = n*Na n (C) = N/Na n (C) = 6,45*10²²/6,023*10²³ N (C) = 0,1075mol

M (C) = 12 n=m/M m (C) = 0,1075mol*12g/mol m (C) = 1,29g

Explanation:

We use two types of formulas: N=n*Na and n=m/M

N - number of atoms

Na - number of Avogadro 6,023*10²³

n - quantity of substance

m-mass of the substance

M-molar mass (for carbon is 12, we can find it in the Periodic sistem)