What is the mass of 2.6 moles of Ag?

$\text{2.6 mol Ag}$ has a mass of $\text{280 g}$.
Multiply the moles of $\text{Ag}$ by its molar mass (atomic weight in g/mol).
2.6color(red)cancel(color(black)("mol Ag "))xx(107.8682"g Ag")/(1color(red)cancel(color(black)("mol Ag")))= "280 g Ag" (rounded to two significant figures)