J.R. S. answered 09/12/23
Ph.D. University Professor with 10+ years Tutoring Experience
The heat LOST by the hot metal MUST EQUAL the heat GAINED by the water and the calorimeter. Also, the final temperature of the metal, the water and the calorimeter will all be the same as the temperature will equilibrate among the three.
First, we'll determine the heat lost by the metal:
q = mC∆T
q = heat = ?
m = mass = 100 g
C = specific heat = 0.57 J/gº
∆T = 110º - Tf where Tf = final temperature
q = (100 g)(0.57 J/gº)(110º - Tf) = 6270 - 57Tf
Next, we find the heat gained by the water and the calorimeter combined:
For water: q = mC∆T = (120 g)(4.184 J/gº)(Tf - 18º) = 502Tf - 9037
For calorimeter: q = mC∆T = (300 g)(0.30 J/gº)(Tf - 18º) = 90Tf - 1620
Combined: 502Tf - 9037 + 90Tf - 1620
Now set heat lost by metal (6270 - 57Tf) equal to heat gained by water + calorimeter and solve for Tf:
6270 - 57Tf = 502Tf - 9037 + 90Tf - 1620
16927 = 649Tf
Tf = 26.1ºC = FINAL TEMPERATURE