Question

one kilogram of R-134a fills a 0.06 m^3 rigid container at an initial temperature of 0 C. the container is than heated until the refridgerant becomes saturated vapor . the process is:

a. constant pressure

b. constant temperature

c. constant volume

d. constant enthalpy

Answer 1

The process of heating to make a substance saturated vapor is done during phase change from liquid state to vapor state. In this case, the R-134a is at a higher pressure (as its normal boiling point is ~- 26-degree celsius). Thus, it undergoes a phase change in the given process, and phase change typically happens at a constant temperature. But the vessel here is also given to be rigid. Hence the most appropriate option to be chose would be Option c: constant volume because the rigidity of the container cannot be violated at any cost.