Respuesta :

You need to use q = mc(delta t) 
Solve for c: 

c = q / m(delta t) 

q = 55.o J 
m = 11.0 g 
delta t = 24.5 - 13.0 = 11.5 deg C 

c = 55 J / 11.0 g)(11.5 C) 
c = 0.435 J/ g C