UTF-8Hydrophobic EffectExploring why two liquids do or do not mix
Here are two different liquids that appear 'layered' and do not mix or dissolve in each other. Aqueous and organic liquids will layer as you have probably seen before, but there are many examples in of liquids in nature that behave this way and it is not necessary that one is water and ther is 'organic'. We call liquids that won't mix mutually immiscible. The simulation below has a pink liquid (particles of type "Nt") and a green liquid (particles of type "Pl"). The simulation is carried out with gravity turned on.
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Please answer the following questions/challenges by typing directly into this page. To do so, click on the 'Save' button near the top-left of this page, then click on 'Edit' to type directly in the page. Finally, save the changes you've made and submit your work by clicking on 'Webspace' above and 'Submit current page' (you will have to log in to Mol. Workbench).
Questions/challenges:
1.) If you play the simulation, the two particles will not mix. Can you 'break' the model and cause the model to stop behaving this way? List all the changes you made below and how each change destroyed the layering behavior.
Raising the temperature/kinetic energy; this is because as stated in the Gibbs free energy equation G=H - TS. So as temperature increases the entrophy increases enabling the particles to mix. On the other hand the particles tended to stay separated at low temperatures. Also can decrease the radius of the pink particles. As a result causes them to be closer together. Change the size of the pink particle allowing them to have a greater density than the green particles.
2.) Can you make specific changes that cause the layers to flip (i.e. the pink partilces to arrange below the green)? List all the changes you made that succeeded in inverting the layers.
Changing the density of the pink particles to be denser compared to the green particles; as well an increase in temperature was needed to allow the heavier red particles to settle towards the bottom.
3.) Can you make another change so that the two liquids mix and form a solution. Explain what you did below to achieve that.
We got complete mixing by setting the red and green particles to equal mass, equal equilibrium distance between red-red, green-green, and set the equilibrium distance between the red-green as equal to or lower than the equil distance of the red-red and green-green.
Changing the density of the pink particles to be denser compared to the green particles; as well an increase in temperature was needed to allow the heavier red particles to settle towards the bottom.
After you've answered the questions on your own, discuss them with your group to determine what changes they made to accomplish the desired behavior. What's the best strategy? Report your group's consensus on this Google Doc: http://tinyurl.com/l3vqo8j
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