Compressed air is stored in a pressure bottle with a volume of \(100 \mathrm{~L}\), at \(500 \mathrm{kPa}\) absolute and \(20^{\circ} \mathrm{C}\). At a certain instant, a valve is opened and mass flows from the bottle at \(\dot{m}=0.01 \mathrm{~kg} / \mathrm{s}\). Find the rate of change of temperature in the bottle at this instant.