A piece of silver was heated to 44℃ and placed in a coffee cup calorimeter containing 150 mL of water. The temperature of the water increased from 23℃ to 32℃. Calculate the mass of the piece of silver. Given: Cs, water = 4.184 J/g℃; Cs, silver = 0.24 J/goC; density of water = 1g/ml