Recent content by Mike Dacre

  1. Mike Dacre

    Speed and pressure relative to a piston (fluids)

    Yeah, I thought of that, but the question says that the water is being released and that the operator controls the water speed. Would it not be the case that the speed that the water initially strikes the piston with would result in a greater total movement of the piston? Taking absurd examples...
  2. Mike Dacre

    Speed and pressure relative to a piston (fluids)

    The Khan Acadamy seems to back me up here: The idea that regions where the fluid is moving fast will have lower pressure can seem strange. Surely, a fast moving fluid that strikes you must apply more pressure to your body than a slow moving fluid, right? Yes, that is right. But we're talking...
  3. Mike Dacre

    Speed and pressure relative to a piston (fluids)

    I am studying for the MCAT and I got an interesting question from a Kaplan book: 15. A water tower operator is interested in increasing the pressure of a column of water that is applied to a piston. She hopes that increasing the pressure will increase the force being applied to the piston. The...
  4. Mike Dacre

    NBS vs radical HBr in the bromination of olefins

    Thank you, I found it after some searching. The answer is that the above mechanisms do compete with each other in all cases, however, when NBS is used, allylic hydrogen substitution wins. In the halogenation of a pi bond, either by ionic or radical mechanisms, the first step of the reaction is...
  5. Mike Dacre

    NBS vs radical HBr in the bromination of olefins

    I am having some trouble understanding why different sources of bromine radicals supposedly brominate an alkene at different positions. What I mean by this: In the first example, the Bromine radical attacks a hydrogen at the allylic position and then a termination reaction results in a Bromine...
  6. Mike Dacre

    Mixed Melting Point of Two Pure Solid Crystals

    Great, thank you all for your help. That is actually an interesting kinetics question, and one that I couldn't find an answer to after a little brief searching. If they behave anything like my two unknowns for my organic chemistry lab, they start melting very quickly. Does anyone know the...
  7. Mike Dacre

    Mixed Melting Point of Two Pure Solid Crystals

    Hi Bystander, thank you for your help but I would like a little extra clarification if possible. Unfortunately, the course I am taking has a separate lab and lecture that aren't always synchronized and I have not learned about Gibb's Phase Rule in class yet. I just went to YouTube and Wikipedia...
  8. Mike Dacre

    Mixed Melting Point of Two Pure Solid Crystals

    I understand why an impure solid will have a decreased melting point, however, in my recent organic chemistry lab section I mixed two finely ground pure solids together and observed that the mixture melted at a lower temperature than either pure solid. I understand this in principle, but...
  9. Mike Dacre

    Does KP predict reaction direction?

    Thank you, that makes sense to me. The reason for my confusion was that I was not sure that they were necessarily describing exactly the same thing. In your example, one could be describing if the ball was going to fall, and another could be describing how big the ball was. In hindsight, I...
  10. Mike Dacre

    Evolution, short term or long term adaptation?

    I agree, this is a very important concept and many essential biochemical processes fall into this category. The original question is whether long term or short term adaptation contribute more to evolution. I think that question is nebulous enough that we are having a discussion largely about...
  11. Mike Dacre

    Does KP predict reaction direction?

    That confuses me a little. Are you saying that an equilibrium constant greater than 1 does not always favor the products?
  12. Mike Dacre

    Can pull up exercise increase height?

    Hanging from either your arms or your feet does reverse the pressure on the inter-vertebral disks (the compression pressure has now become an expansion pressure), and so it makes sense that it will increase your height. However, this increase is likely to be very marginal at best, my guess is on...
  13. Mike Dacre

    Does KP predict reaction direction?

    You are right, I meant pressure. And yes, I know the relationship: K_P = K_C RT^{\Delta n} What I am curious about is if it is possible for there to be a situation where KC is greater than 1 but KP is less than 1. Hypothetically if Δn is negative then from the math alone KP can be less than 1...
  14. Mike Dacre

    Evolution, short term or long term adaptation?

    Pythagorean, How can a trait that has no value in a population provided a fitness benefit? I think that what you are arguing is essentially a semantic point. 'long term adaptation' really just means that a trait has continued to be useful for a long period of time. However, the driving forces...
  15. Mike Dacre

    Does KP predict reaction direction?

    I think I already know the answer to this, but I can't find an easy reliable source online. Does KP predict reaction direction in the same way as KC? i.e. If KP is greater than 1, the reaction favors the products, and if it is less than 1 it favors the reactants? Or is it just that if KP is...
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