Answer:
15 grams of water will absorb 2,500 Joules in going from 20.0 to 60.0 C.
Step-by-step explanation:
The heat involved in raising a mass (m) of a substance with a specific heat (c) from one temperature to another (Delta T) is given by:
Heat = mc(Delta T)
2,500 Joules = m*(4.186J/gC)*(60C-20C)
2,500 Joules = m*(4.186J/gC)*(40C)
2,500 Joules = m*(4.186J/gC)*(40C)
m = (2,500J)/(4.186*40J/g)
m = 14.93 grams