I don't understand about entropy and the second law about energy. Second law states: Every energy transformat

Question

ion leads to an increase in the amount of disorganization or disorder (disorder is the same thing as entropy)

My Biology book states that because when hydrogen ions (H+) are distributed randomly on either side of the membrane, no additional energy is needed to keep them that way, and the entropy, or disorder, of their arrangement has increased. The result is a more stable arrangement of H+ ions.

I need help understanding this concept. : (

Thank you all so much in lending your expertise in Biology and Chemistry!!! I now understand the concept due to everyone's input.

Answer 1

An energy transformation is really the same as saying 'work'. And any time work is done, there are energy losses associated with that transformation.

Entropy, while is is a measure of disorder, can also be thought as a measure of 'lack of order'. When energy is 'contained' in some way (be it in a potential chemical reaction, potential or kinetic mechanical energy, or any other way), then there is a certain amount of 'order' to the system. The energy is simply 'setting there' and not being used.

But, when you begin to use that energy to do work (to transform that energy into something useful or into another form), part of the energy involved is 'lost'. The most common form of loss is through friction, thermal radiation, etc. There are more exotic types of loss, such as hysteresis, but they all come down to the same thing: All of the energy that you so carefully 'ordered' to do something (hopefully useful) didn't get used. Part of it was lost and the 'order' (or well-ordering) of the system has been reduced (or it's 'disorder' has been increased) as a result.

Hope that helps ☺


Doug

Answer 2

Entropy can be thought of as the natural tendency of everything to equalize. Air in a balloon leaks out until pressures are equalized. Red smoke distributes itself and becomes invisible, and a strong odor dissipates until it is undetectable - given enough volume and time.

In the case of ion concentrations on either side of a membrane, this tendency has been achieved when the ions have become distributed evenly - called the state of maximum entropy.

To reduce entropy means to increase order, or to gather or increase the concentration of something (heat, red smoke particles, whatever). Gathering takes energy, while maximum entropy is like idealized laziness, the natural result of any otherwise uncontrolled process or activity (study how a cat or dog relax, or how the wood in a fire transforms and settles into ashes and the heat "goes away"). Evenly distributed ions is the laziest arrangement nature can devise.

Don't think too hard about it. Keep it simple. Forget things like like charges repelling, heat convection, and all that other fancy stuff. Let it soak in for a while.

Good luck!

Answer 3

Try thinking about the hydrogen ions as little blue balls, and the other ions as little red balls. They are all in a box, and the box is being jiggled so they get stirred up. The jiggling is like the thermal mixing (diffusion) in your hydrogen ion example. How will the balls be arranged in your box- with all the red ones on one side and all the blue ones on another? No, they will tend to get mixed up - "distributed randomly". Randomly mixed is the state of maximum entropy - and that's how they will end up, all else being equal.

Now lets imagine a membrane down the center of your box, dividing it in half. This membrane has special holes in it that can move blue balls from one side to the other, but it requires energy to move the balls. The easy thing for the membrane to do is not worry about which side the blue balls are on, and just let the balls mix.

But if the membrane needs more blue balls on one side and more red balls on the other side, it's going to have to use energy to run the special ball sorting holes that pump blue balls to one side and red balls to the other side. So the point is that if the membrane is OK with the blue and red balls being randomly distributed, it doesn't have to spend the energy pumping blue balls to one side. The second law of theromdynamics just says that if you don't put the energy into running the ball sorting pumps, then things will get randomly mixed up. The entropy just measures how mixed-up the balls are, and when they are all mixed up as much as they can be (distributed ramndomly), the entropy is as big as it can get.

Answer 4

Think of it like having water in a container with a divide in it and all the water to one side. Then when you suddenly pull that divide out the water automatically evens out. It's the same in your cell. If all the H+ ions are on one side of a membrane then they will even out as well and they will be equal concentration and so more stable, because they won't go back, just like the water won't go back to just one side of the container. Because the arrangement is random, it increases the disorder so entropy will increase.