$(25)$ A $300k\frac{J}{m}in$ refrigeration system that operates on an ideal vapor$-$compression refrigeration cycle with refrigerant $134$a enters the compressor as saturated vapor at $140$ kPA and is compressed to $800$ kPA $.$ Determine: $($a$)(10$ pts $.)$ the mass flow rate of the refrigerant, $($b$)(15$ pts$.)$ the $CO{P}_H($in other words operating in the heating mode$).$