Calculate the change in entropy of 1 mol of an ideal gas with Cp = 3.5R undergoing the following processes:

a) taken reversibly from 25C, 1 atm to 50C, 5 atm.

b) taken from 25C, 1 atm to 50C, 5 atm by first heating to the final temperature with a 100C source at constant volume, then quickly compressing to the final pressure by exposure to a 10-atm source, and finally allowing heat transfer to a 10C reservoir to bring the gas back to 50C.