Answer:
2,092 J is the amount of heat energy released when 50.0 grams of water is cooled.
Explanation:
Mass of water = m = 50.0 g
Initial temperature of the water = 
Final temperature of the coffee = 
Specific heat of water = c = 4.184 J/g°C
Heat required to cooled from 20°C to 10°C= Q



Q = -2,092 J
Negative sign means that energy is lost.
2,092 J is the amount of heat energy released when 50.0 grams of water is cooled.