Question

How many molecules of ascorbic acid (vitamin c, C6 H8 O6) ARE in a 500mg tablet?

Answer 1

$$n(C_6H_8O_6) =\frac{m}{M} = \frac{0.5}{176.12} = 0.00284 mol$$

$$N = N_A\times n = 6.022\times 10^{23}\times 0.00284 =1.71\times 10^{21} molecules$$