J.R. S. answered 03/28/23
Ph.D. University Professor with 10+ years Tutoring Experience
The heat LOST by the hot metal MUST equal the heat GAINED by the cooler water.
q = mC∆T where q = heat; m = mass; C = specific heat; ∆T = change in temperature
heat lost by metal = q = mC∆T = (55.0g)(C)(100 - 28.5º) = (55g)(C)(71.5º) = 3932.5 C
heat gained by water = q = mC∆T = (100.0g)(4.184 J/gº)(28.5 - 25º) = 418.4(3.5) = 1464.4
Set these two equal to each other and solve for C:
3932.5 C = 1464.4
C = 0.372 J/gº