So for Isothermal, there is no change of T so hence delta U is 0. However, if there isn't a change of temperature, how is there a change of Q? I thought heat was the flow of energy of different temperatures. This confuses me for adiabatic as well. With no heat, how is there a temperature change. Also, apparently adiabatic processes, the change of temperature must be negative. However, why? For a second, I thought it may be because there's no added heat but there shouldn't be heat leaving either. I feel like this is all tangled up in my head and I would appreciate some clarification!