Recent content by vaazu

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    Setup Thermodynamic Cycle for Enthalpy of Hydration of Mg2+ Ions

    yeah, the solvation enthalpy, from solid to liquid, then the enthalpy of Cl- in the solution. The change of the enthalpy in the cycle should be 0, but how to find the difference in the MgCl2(s) and the gas phases?
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    Setup Thermodynamic Cycle for Enthalpy of Hydration of Mg2+ Ions

    Homework Statement Set up thermodynamic cycle for determining the enthalpy of hydration of Mg2+ ions The following enthalpies are given Sublimation of Mg ionization energies of Mg dissociation enthalpy of Cl2 electron gain enthalpy of Cl enthalpy of solution of MgCl2(s) enhalpy of...
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    Gas is isothermally and reversibly condensed

    Homework Statement gas is isothermally and reversibly condensed n=2(mol) T=337K H(vap)=35.3kJ/mol find w, q, U, H Homework Equations The Attempt at a Solution H=-H(vap)*2=-70.6kJ/mol H=U+n(g)RT w=-n(g)RT n(g)=-2 w=5.6kJ So U=H-w U Should be -70.6-5.6=-76.2, but the book...
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    How Do You Calculate the Dipole Moment of CO2 with a 120 Degree Bond Angle?

    Homework Statement r-bond length (in anströms) q-charge (in debyes) CO2 r(CO)=1.1867 q(C)=1.1352 q(O)=-0.5676 angle between them is 120 deg Homework Equations The Attempt at a Solution I know I have to make vectors and then add them, but I don't know how to make the vectors. I...
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    Salt crystal forms after 3 days of evaporation

    i think you don´t have to divide the sum of atoms by 2 to get the number of Na+ or Cl- atoms, because if you have, let's say 1mole of NaCl, then it has 1mole of Na+ and 1mole Cl- atoms, which means twice as many particles as in NaCl.
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    Cl-C-Cl vs H-C-H Bond Angles in CH4 & Dichloromethane

    Chlorine has three free electron pairs, hydrogen has none. Because of the electon pairs chlorine atoms repell from each other more strongly so the Cl-C-Cl bond angle should be bigger than H-C-H. I am not sure of this, but it seemed logical to me.
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    Silicon vs. Carbon: Why is Silicon-Based Life So Unlikely?

    But if we would assume that the pressure and temperature wouldn´t be the same in the other enviroment. Then could Si compounds be more stable? And the oxidizer (i hope it´s like that in english) wouldn´t be O. For example F. Then SiF4 (it should be a gas) could play the role as CO2. Or is F so...
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    Silicone Super Ball: Learn About Its Properties & Chemistry

    Is the polymer atactic? if it is, how can it be achieved, probably can't be explained in a simple way? what properties would it have if it were for example isotactic?
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    Silicone Super Ball: Learn About Its Properties & Chemistry

    Hello, I have some questions about the "Silicone super ball". Heres a link for it [PLAIN]www.flinnsci.com/Documents/demoPDFs/Chemistry/CF0758.50.pdf[/URL] I have to make a presentation about it so I need to educate myself on the topic. When the solution is mixed a new polymer forms...
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    How Do You Calculate the Redox Potential for This Reaction?

    Yes the J was typo, it should be I. Don´t know what was I thinking. Could you explain me, how the Eo is calculated, or what should I be looking for? Is the reaction standard potential calculated between the pair which actually exchanged electrons Cr(3+) and I2, or somehow between the chrome and...
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    How Do You Calculate the Redox Potential for This Reaction?

    Homework Statement I have to calculate the redox potential of this equation: Cr2(SO4)3 + 4K2SO4 + 3J2 +7H2O <=> K2Cr2O7 + 6KJ +7H2SO4 I used the nernst equation to calculate the potentials of 2Cr(3+)+7H2O -> Cr2O7(2-) +14H(+) +6e(-) and I2 +2e(-) ->2J(-) which were -1.42V and 0.51V, all...
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    What is the empirical formula of this compound help?

    10.34/16 < 18.53/23 and 25.87/32, but you have more O atoms in your formula than Na and S. How is that? I got Na5S5O4*22H2O, but that's probably not right.
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    Difference in simple and fractional distillation

    I found on the internet that fractional is used when the differences in boiling points are below 25C, and that there are more than 2 or 3 substances in the mixture, but i didn´t figure out what's the difference in apparatus or how the substances are purified in fractional distillation. Could...
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    Discover the Truth About Benzene in Organic Chemistry: Facts and Myths [SOLVED]

    yes, second and third are right. Benzene doesn´t have alternating single and double bonds, it´s just a way of expressing the molecule. Some electrons, don´t know how many of them are delocalized in benzene so the bonds aren´t single nor double.
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    Question about the definition of functions

    Homework Statement Y={y:y=f(x), xe(can´t find the right symbol, but it should be belongs)X} is the changing region (is it like that in English?) of the function f function f-s graphic is a region of points in the xy plane is defined as (f)={(x;y):y=f(x),x e X0 Homework Equations what do...
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