A student places several ice cubes into a glass beaker that is initially at room…
PHYSICS · Multi-part · A Level · Physics · Further mechanics and thermal physics · Further mechanics and thermal physics
Problem
A student places several ice cubes into a glass beaker that is initially at room temperature (approximately 22 °C). After five minutes, the temperature of the liquid–solid mixture has stabilized at 0 °C while the beaker feels noticeably colder to the touch.
Answer the following questions about the energy changes occurring during this process. Assume the pressure remains constant throughout.
(1) Describe the direction of energy transfer between the ice–water system and its surroundings as the ice melts.
(2) State whether the melting of ice under these conditions is classified as an endothermic or an exothermic process, and justify your answer with reference to the observed temperature change.
(3) Explain the sign (positive or negative) of the enthalpy change ΔH for the melting of ice at 0 °C and 1 atm, making explicit reference to the system–surroundings framework.