The calculated distance (air line) between Morozovsk and Rostov-na-Donu is approximately 125 miles respectively 201 kilometers.
By car or train, the actual journey to Rostov-na-Donu is certainly longer, as only the direct route (as the crow flies) between Morozovsk and Rostov-na-Donu has been calculated here.
Air line (approximately)
201 kilometers
108 nautical miles