On your wedding day your lover gives you a gold ring of mass 3.78 g. 50 years later its mass is 3.16 g. On the average how many atoms were abrated from the ring during each second of your marriage? The atomic mass of gold is 197 u

Answer 1

The ring lost 0.62 g in 50 years. That is 0.62/197 = 3.15*10^-3 moles. Multiply by Avogadro's number for the number of atoms lost: 1.90*10^21.
Next, divide that by 50 years, in seconds.

I get about 3*10^13 atoms/second