The calculated distance (air line) between Kostiantynivka and Chornukhyne is approximately 40 miles respectively 64 kilometers.
By car or train, the actual journey to Chornukhyne is certainly longer, as only the direct route (as the crow flies) between Kostiantynivka and Chornukhyne has been calculated here.
Air line (approximately)
64 kilometers
35 nautical miles