We first have to find Q calorimeter
Q calorimeter = C (delta T)Â
C= heat capacity in J/oC, not small c ( specific heat capacity)Â
delta T= change in T (oC) = final T - initial TÂ
Q calorimeter = 10.4 J/oC (30 oC - 25 oC)
Q calorimeter = 52 JÂ
Remember,Â
Q calorimeter = - Q surrounding
The (-) negative sign stands for heat being released.Â
So ,Â
Q surrounding = - 52 JÂ
In other words, the iron releases 52 J .
The calorimeter absorbs the entire 52 J and heat rose from 25 - 30 oC.Â
Answer: 52 J