1. The problem statement, all variables and given/known data A hot (800 K) iron nail of mass 150 g is placed into a 1.0 kg of water at 25°C. What is the common temperature of the 2 objects once they have reached thermal equilibrium? Assume no change of state of the water. Heat capacity of iron nail is 450 J/kg/K Heat capacity of water is 4138 J/kg/K 2. Relevant equations Q=mc∆T 3. The attempt at a solution Q lost in nail=Q gained in water let T = final temperature 0.15*450*(800-T)=1*4138*(T+25+273) T=-280.38 K I don't know why it is negative. Can someone explain what I did wrong?