1. The problem statement, all variables and given/known data A spherical air bubble in a lake expands as it rises slowly to the surface. At the point it starts to rise, the pressure is 2.00 atm, the temperature of the water is 10.0 ∘C, and the radius of the bubble is 5.00 × 10^−3 m. At the surface, the pressure is 1.00 atm and the temperature of the water is 20.0 ∘C. A) What is the final-to-initial volume ratio for the expanding bubble? B) What is the change in thermal energy of the bubble? 2. Relevant equations For part B: P1V1/T1=P2V2/T2 For part A: I honestly have no idea. I've tried messing around with change in thermal energy = N*Cv*deltaT but I'm not getting any where. 3. The attempt at a solution This problem is under the section for isobaric and isothermal ideal gas processes, but I'm not seeing how it is either.