I understand if isobaric work is done on a system then its internal energy must increase, meaning that the temperature must increase as well. However, according to Charle's Law, volume is proportional to temperature which means that if volume decreases, so must temperature. How can the two happen at the same time? There seems to be a contradiction. Doing isobaric work involves decreasing volume leading to increased internal energy and temperature. But according to Charles' Law, the temperature must decrease in this situation.