Molar heat capacities of an ideal gas

[Hyein Cha 2I]

In section 8.9 of textbook, it states that Cp,m is larger than Cv,m since not all the heat supplied is used to raise the temperature at constant pressure. I didnt really understand why not all heat is used to raise temperature at comstant pressure. Can someone please explain?

[Ethan Vuong 3G]

I think this has to do something with the fact that as the volume gets larger, there will be more work to push the air.

[Haocheng Zhang 2A]

Since PV=nRT, in order to increase the temperature and keep constant pressure, the volume has to increase. When the volume increases, the gas is doing work,which requires energy. Therefore Not all of energy is used to raise temperature.