Heat Transfer

Abstract

We are now stepping into the traditional physical chemistry area known as thermodynamics. Thermodynamics is concerned with a change of the total energy of a system. A system is a body which performs work (–w) or gives away heat (−q); the same body can also receive work (+w) or heat (+q). Notice the sign: when you carry out work or give away heat (you hold someone’s cold hands) the sign is minus. When you receive work (a friend carries your schoolbooks) or heat (warming up your hands on a campfire) the sign is plus. Come to think – it is the same with personal finances: the money given definitely has a minus sign. In the next few examples we will look into what happens when heat is exchanged between two bodies.