EMB ERJ 145 ER/LR
Fatigue; Situational Awareness
Deviation - Speed All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Wake Vortex Encounter
Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Environment - Non Weather Related; Human Factors
[We] departed [ORD] 22L with left turn to 140 heading. Initial fix was EARND which is in the '250 KT until advised' departure sector. Above 10;000 FT; [we] encountered brief significant wake turbulence. Captain adjusted rate of climb to increase airspeed slightly as a response to wake turbulence. Although we had discussed the 250 KT restriction on the ground; it obviously slipped our mind as a result of the wake turbulence. The Captain then resumed the normal takeoff profile before obtaining 'normal speed' clearance and we were queried by ATC about our speed. We reported 'slowing to 250' and were then assigned a heading possibly to compensate for our excess speed. No further requests or comments were made by ATC and flight was completed without further incident.
An EMB-145LR First Officer reported a wake vortex encounter climbing out of ORD that was distracting enough they forgot the 250 KT restriction and ATC called them on it.