A spherical balloon contains 2 kg of R-22 at 0C, 30% quality. This system is heated until

Question:

A spherical balloon contains 2 kg of R-22 at 0C, 30% quality. This system is heated until the pressure in the balloon reaches 600 kPa. For this process, it can be assumed that the pressure in the balloon is directly proportional to the balloon diameter. How does pressure vary with volume and what is the heat transfer for the process?