Chemical Reactions Links

The Laws of Thermodynamics

Definitely physics, right?

Wrong.

Thermodynamics - or the study of the conversion of energy into work and heat - governs processes in all three of the basic sciences. In biology, thermodynamics explains metabolism and in chemistry thermodynamics explains the hows and whys of reactions that use or produce heat.

The Laws

The First Law goes a little something like this:

Energy is Conserved!

That means that you can't get rid of it, no matter how hard you try. Energy is here to stay whether you liek it or not. It changes from one for to another, but it never just disappears.

This is a very helpful law when it comes to figuring out the mysteries of the universe. It is so much easier to find something when you know it HAS to be there!

Watch a short video about this topic here.

The Second Law is even cooler than the first and it states:

The entropy of the universe is always increasing in a closed system

...or basically, if you don't put energy into things, they run down. You clean your room and it gets dirty again. You heat up your food in the microwave and then forget it is there - it gets cold again. Such is the Second Law of Thermodynamics.

We know this to be intuitively true - we see that we must put energy and work into things all the time.

The second law can be stated in a few other ways as well, for instance:

Energy tends to disperse

Heat flows from a hotter space or object to a cooler space or object

Entropy is just a fancy before and after picture of things or a measure of how organized or disorganized energy is in a system. Ok - now that we have that out of the way - on to the good stuff - endothermic and exothermic reactions!