A stainless-steel spoon initially at room temperature (22 °C) is left immersed for two minutes in a bowl of tomato soup whose bulk temperature is 85 °C. Assume the soup is well-stirred so that its temperature remains uniform and that heat exchange with the surrounding air is negligible.
(a) Identify the direction of thermal energy transfer between the soup and the spoon during the two-minute interval.
(b) Using particulate-level reasoning, describe why energy is transferred in that direction when the particles of the spoon collide with particles of the soup.
(c) Predict qualitatively how the average kinetic energy of the particles in the spoon and in the soup change during the interval.
(d) State the condition that must be satisfied for the soup–spoon system to reach thermal equilibrium, and explain how the molecular collision model accounts for this condition.