Flight Keflavík International Airport departs from Reykjavik Keflavík International Airport at 16:25 and arrives at Chicago O'Hare International Airport at 18:15.
The flighttime is about 7h 50m. The distance travelled ("as the bird flies"): 7278 Km. So the average speed is roughly 929 Km.
There is an 6 hour time difference between Reykjavik and Chicago