Recent content by broegger

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    Basic probability exercise

    :-) Precisely. Hopes somebody weighs in...
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    Basic probability exercise

    Hmm. In (a) there are two ways of getting all assignments wrong (if the correct one is 123, then these are 312 and 231) and there are 3*2*1 = 6 possible assignments. If his guesses are random this yields Pr(all wrong) = 2/6 = 1/3. In (b) I count 9 ways of getting all assignments wrong out of...
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    Basic probability exercise

    Yeah, I think I'll do that, although it gets rather complex in (b). A slight problem though: when I count the combinations I get 3/8 in (b), but when I calculate it using the multiplication rule I get 1/4 :eek:
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    Basic probability exercise

    Hi. I'm a math instructor and this problem is given to 1. year economics students. 1. The problem statement In an episode of the TV show "All in the Family", Mike claimed that he could identify different brands of cola by taste alone. He was challenged and presented with three glasses, one...
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    Conditional distribution

    I've been staring at this for hours. Any hints? Let the vector Y = (Y_1,Y_2,\dots,Y_k) have a multinomial distribution with parameters n and \pi = (\pi_1,\pi_2,\dots,\pi_k): \sum_{i=1}^{k}Y_i = n, \quad \sum_{i=1}^{k}\pi_i = 1 Show that the conditional distribution of Y_1 given...
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    Optical isomerism

    It's in the context of simple http://wwwchem.uwimona.edu.jm:1104/courses/CFT.html". I don't think there's any unobivious rules here, but I don't know...
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    Optical isomerism

    I see your point. If we assume that every H2O molecule occupies one ligand space and does not interact with it's neighbors -- would I then be correct? It's an introductory course, so I assume there's no pitfalls.
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    Optical isomerism

    Hi. I'm asked the following question: What isomers does the complex [\text{Fe}(\text{H}_2\text{O})_6] give rise to? Is it optically active? My answer to the first question would be 'none': The 6 identical H2O molecules are arranged in an octahedral fashion around the central Fe-atom, so...
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    Bonding etc.

    c) Still in the dark. Can't relate these things to the activation energy... sorry. f) Oxygen is more electronegative than nitrogen, so the OH-molecule has a greater dipole strength than the NH-molecule and therefore the hydrogen bond is stronger in the former case (O-H---O). Right? Thanks...
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    Bonding etc.

    Hi. I need help with (part of) this exercise: c) By considering the differences in bonding determine which of the combustion reactions (in part a) I have written combustion reactions for the following hydrides: B2H6, CH4, NH3 and H2S) must be expected to have the lowest energy of activation...
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    Solubility problem

    Hmm, not sure. But I think I know how to do it now. Thanks.
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    Solubility problem

    It will shift to the right, so the solubility will go up (consistent with my result.) I should compute the I3- concentration and add it to the I2(aq) concentration to find the new solubility, right?
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    Solubility problem

    Hi. I'm preparing for a chemistry exam and I have trouble with this former exam problem: The solubility of I_2\text{(s)} in water at 25ºC is 0.0013 M. Calculate the solubility of I_2\text{(s)} in a 0.1 M solution of KI(aq) by considering this equilibrium: I_2\text{(aq)}+I^-\text{(aq)}...
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    Enthalpy of hydration

    I have no idea, just quoting from the book, basically. Doesn't Li- and Cs-solids exist? I'm a lousy chemist, I know. I would think that "quietly" means slow and "violently" means fast, so the statement is that the reaction rate of Cs + water is larger than the reaction rate of Li + water. I...
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    Enthalpy of hydration

    The Li atoms are smaller, but how does that affect the reaction?
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