Thermodynamics of Pharmaceutical Systems
An Introduction for Students of Pharmacy
Chapter One
ENERGY AND THE FIRST
LAW OF THERMODYNAMICS
1.1. FUNDAMENTAL CONCEPTS
Temperature and the Zeroth Law. The concept of temperature is so familiar
to us that we may not comprehend why scientists two centuries ago tended to confuse
temperature with heat. We will start with the notion that temperature corresponds
to "degree of hotness" experienced as a sensation. Next we assign a
number to the temperature based on the observation that material objects (gases
and liquids in particular) respond to "degree of hotness" through variations in their
volumes. Thus we should be able to associate a number (its temperature) with the
volume of a specified amount of material. We call the instrument designed for this
purpose a thermometer.
The first requirement in setting up a scale of temperatures is to choose a zero
point. In the common Celsius or centigrade scale we set the freezing point of water
(which is also the melting point of ice) at 0ºC [more precisely, 0ºC corresponds to
the freezing point of water (called the "ice point") in the presence of air at ... read full excerpt from Thermodynamics of Pharmaceutical Systems: An Introduction for Students of Pharmacy ebook
