An insulated aluminum calorimeter cup (mass = 45.0 g) initially contains 100.0 g of…
PHYSICS · Multi-part · A Level · Physics · Further mechanics and thermal physics · Further mechanics and thermal physics
Problem
An insulated aluminum calorimeter cup (mass = 45.0 g) initially contains 100.0 g of liquid ethanol at 10.0∘C. A 150.0 g sample of liquid water at 70.0∘C is rapidly poured into the cup, and the mixture is stirred until equilibrium is reached. No phase changes occur, and any heat exchange with the external environment is negligible unless otherwise specified.
Specific heat capacities:
• Ethanol: 2.44Jg−1∘C−1
• Water: 4.18Jg−1∘C−1
• Aluminum: 0.897Jg−1∘C−1
(a) Calculate the final equilibrium temperature of the entire system (ethanol, water, and aluminum cup).
(b) Determine the quantity of heat absorbed by the aluminum cup as it warms to the temperature calculated in part (a).
(c) If 5.0 % of the thermal energy released by the hot water escapes to the surroundings instead of being absorbed by the ethanol and the cup, predict qualitatively whether the actual final equilibrium temperature will be higher, lower, or unchanged compared with the value calculated in part (a). Provide a concise justification.