Recent content by leumas614

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    Exothermic reaction moves forward with increase in Temp?

    I did an equilibrium calculation with some chem software that I have and it told me that a syngas reaction CH4+0.5O2\rightarrow 2H_{2}+CO which is an exothermic reaction will proceed to completion at high temperature. If you increase temperature, that should drive the reaction backwards...
  2. L

    Help calculating equilibrium temperature for a reaction

    Keq is equal to e^{-\frac{\Delta G}{RT}}. Just find \Delta G by using a table of thermodynamic data.
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    Stress field in cylindrical coordinates

    Can anyone please explain the stress fields in cylindrical coordinates? What is the difference between \sigma_{rz} and \sigma_{\theta z}? What is the difference between stress in the r axis and stress in the \theta axis? Thanks
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    Medical What caused the sudden loss of breath after a fall?

    http://en.wikipedia.org/wiki/Getting_the_wind_knocked_out_of_you
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    Material science v.s. chemical engineering?

    at the graduate level the differences become blurred. Many ChemE's do more materials research and many MatSci's do more ChemE research. They are very similar when it comes to research
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    What is the temperature and pressure relationship during the pump down process?

    ok, I got it. I asked the TA and he said the key relationship that I was missing is this: \frac{dn}{dt}=n\frac{Sp}{V} The units work out. So I worked it out from there. What you can do then is say U=H_{out}n_{out} since H_{in}n_{in} is zero because there is no mass flowing into...
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    What is the temperature and pressure relationship during the pump down process?

    I still don't quite follow what you're suggesting. The volume does not change because we took the system to be the inside of the chamber which is rigid. Using dV/dt would only work if the chamber was not rigid. But then if the volumetric flow rate is not the molar flow rate than it has no...
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    What is the temperature and pressure relationship during the pump down process?

    But this is what I don't understand. The volumetric flow rate is not constant because the tank is draining so presumably the amount of molecules flowing out of the tank is changing with time. So I don't know what the volumetric flow rate is. I understood the Sp in the question to mean, it...
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    What is the temperature and pressure relationship during the pump down process?

    You get Cv\frac{V}{R}\frac{dP}{dt}=\frac{dU}{dt} So we can relate U with P but you still don't have an expression for P so only one equation with two unknowns. You can't replace P with an expression for T because T is also unknown. Here's what I did. dU=d(Hn) but both H and n are...
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    What is the temperature and pressure relationship during the pump down process?

    Yes, I took the time derivative of PV=nRT holding V constant. V \left(\frac{dP}{dt}\right)=R\left(T \frac{dn}{dt}+n \frac{dT}{dt}\right) dU=nCvdT \frac{dU}{dt}=Cv\left(n\frac{dT}{dt}+T\frac{dn}{dt}\right) from energy balance, dU=Hdn integrating gets U=Hn which equals U=(U+PV)n...
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    What is the temperature and pressure relationship during the pump down process?

    Can anyone please help me with this problem? Consider the act of evacuating a chamber with a vacuum pump. Vacuum pumping rates are usually given in volumetric pumping speeds, Sp, whose units are typically volume/unit time, e.g., 1 m3/min. In other words, the number of molecules in 1 m3 at...
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    Programs Choosing a major: Chemistry or Engineering

    I recommend doing a search on the site. There should be tons of threads about this.
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    Does Engineering Rely Upon Chemistry?

    I would imagine that Civil and MechE has some chemistry if you're dealing with structures but many times this is incorporated into a general Materials Science requirement. For the most part, the chemistry that you need to know is covered in your other courses. The requirement of one semester...
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    Expected Size of One-Boy Family and Probability of Girls

    What is a one-boy family? How can there be girls in a one-boy family?
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