Concept #1: Changes in Internal Energy
Concept #2: The First Law of Thermodynamics
Practice: 2.5 moles of an atomic hydrogen gas are stored in a cylinder with a moveable piston, sitting in a bucket of ice. The piston is moved SLOWLY, decreasing the volume from 0.03 m3 to 0.01 m3 . How much ice melts during this movement? Work done at constant pressure is given by 𝑊 = −𝑃Δ𝑉, and work done at constant temperature by 𝑊 = −𝑛𝑅𝑇𝑙𝑛 ( 𝑉𝑓/𝑉𝑖 ). Note that the latent heat of fusion for water is 334 kJ/kg.