A student places 150 g of water at into an insulated beaker containing 200 g of water at
PHYSICS · Multi-part · CBSE · Physics · Thermal Properties of Matter · Thermal Properties of Matter
Problem
A student places 150 g of water at 90∘C into an insulated beaker containing 200 g of water at 20∘C. The student predicts, "The cold water will flow into the hot water until the cold water is gone, and the mixture will end up warmer than 90∘C because cold cannot heat itself." Assume that no energy is lost to the surroundings and that the specific heat capacity of water is 4.18Jg−1∘C−1.
(a) Identify the conceptual error in the student’s prediction and briefly state the correct physical principle.
(b) Calculate the final equilibrium temperature of the water mixture. Show all work and include proper units.
(c) Explain, at the particulate level, how collisions between water molecules lead to the temperature you calculated in part (b).