Based on the information in the graph which isotope is the most stable and would therefore not release energy by either fusion or fission?
A. Iron-56(Fe-56)
B. Uranium-235(U-235)
C. Hydrogen-2(H-2)

The concept that should be used here is that heat loss is equal to heat gain. In this item, the heat lost by the aluminum pan should be equal to the heat gained by water. Such that,
              750 g(0.215 cal/g°C)(T - 24) = (10000 g)(1 cal/g°C)(4°C)

The value of T from the equation is equal to 272°C.