A small part with a surface area of 2.62 cm² is plated with a gold coating that is 5.00 × 10^–4 mm thick. The density of  gold is 19.32 g cm^–3. What mass of gold is in this coating? If a barrel plating run has 5000 of these parts in a single barrel, how long would the run take if the current was 15.0 A? (Gold is effectively plated from Au⁺(aq).)