AA 2851 then FX 9791 at O'Hare
Denver → Chicago → Anchorage
Timetable, Chicago time
10:30AA 2851 from Denver at the gate
04:00FX 9791 to Anchorage leaves the gate
17 h 30 apart on the timetable, overnight
FX 9791 leaves 17 h 30 after AA 2851 arrives on the timetable: more than half a day, so not a connection we count.