An insulated Styrofoam cup contains 200 g of liquid water at 25 °C. A 150 g iron bolt that has been heated to 100 °C is quickly placed into the water, and the cup is sealed with a tight lid to prevent any mass exchange with the surroundings.
Assume no energy is transferred to the Styrofoam or the air above the liquid.
(a) Determine the final equilibrium temperature of the water–iron system. Relevant specific heat capacities are cFe=0.45J g−1∘C−1 and cH2O=4.18J g−1∘C−1. Show all work and report your answer to the correct number of significant figures.
(b) Explain, using a molecular-level description, how thermal energy is transferred between the iron atoms and the water molecules until equilibrium is reached.
(c) After the system has reached the temperature calculated in part (a), does any additional thermal energy flow between the bolt and the water? Justify your answer in terms of particle motion.