Recent content by Nerro

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    Entropy-increases & decreases

    Basically entropy signifies the number of states a system can be in. This means that when there are more particles in a system that the system can attain more states. So when solid sodium reacts with water to form sodium ions, hydrogen and hydroxide ions the system gains entropy because there...
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    Standard enthaply of reaction

    Look at reaction (3) as two separate phases, first reaction (1) happens in reverse and then reaction (2) happens. This isn't what happens but all the energies involved here are state functions which means that it doesn't matter how you got to that state, the energy is always the same. This way...
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    Iron compound

    Not to my knowledge but when the hydroxide ions make up only a tiny portion of the total amount of anions, the crytal in it's entirety might still be mostly describable as Fe3O4 and thus magnetic.
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    Iron compound

    You can't really say the powder that makes up rust is either pure Fe2O3 or pure FeO or pure Fe3O4. It is a crystal matrix with Fe(II) and Fe(III) in it and hydroxide impurities at the crystal-air interface. The formula which indicates the crystals composition is usualyl that which best describes...
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    What is Eθ?

    It's not a theta, it's a zero with a line thru it. It denotes the electrode potential of something at standard conditions. (pressure, temperature etc.)
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    Have you ever embarassed yourself academically

    A teacher once wrote something along the lines of A ~B on the blackboard. A girl put her hand up and asked "What does that squiggle mean?". She proved quite definately that stupid questions do in fact exist!
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    Problematic Synthesis of Sodium Acetate

    A better idea might be to heat it over a slow fire in a frying pan. This will give the soln. plenty of surface area from which to evaporate. Don't let it boil for too long, you don't want too many crystals forming. When you see crystalformation starting stop heating immedeately and put the hot...
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    Sun block that promotes Vitamin D production

    Vitamin D is most succesfully synthesized in the skin at wavelengths of 270-290nm, which is just outside of the UVA and UVB spectra. A sunblock that uses salicylic acid as the effective ingredient shouldnt block Vit D production.
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    Two easy questions!

    If you go to university to study chemistry you're going to need to be competent at goniometry, calculus, vectors etc. and matrices ;)
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    Acetylation- acetic acid or acetic anhydride

    Have a look at the quantities of both chemicals you used, if that doesn't point you in the right direction post all the numbers here and I'll have a look at them for you.
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    What drives you towards academic success?

    Becoming better at stuff than other people is fun. I like the looks on the faces of people when I tell them I study chemistry. You're only in it for yourself but it can't hurt to share a little ;) And by the way, someone has to be the best at something, chances aren't that great you'll end up...
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    Absolute Zero.

    I believe heat can be extracted letting for instance liquid hydrogen evaporate on the surface of the container. The evaporation is endothermic and will absorb some of the energy from whatever you want to cool. I'm not quite clear on how to cool something with a laser as a laser will add energy...
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    Unclear about the Heisenberg uncertainty principle

    So \Delta A = \sqrt{\int{\psi^* A^2 \psi d\tau} - (\int{\psi^* A \psi d\tau})^2}?
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    Is there any difference between Miscible and Soluble?

    Miscible is said when two liquids can be mixed with eachother. Water and oil are not miscible but water and ethanol are miscible. Soluble is what you call a substance when it can dissolve into a solvent. Both systems entail a change in entropy and as such will cause the exchange of energy with...
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    Unclear about the Heisenberg uncertainty principle

    Hi everybody, I have a slightly noobish question and I've searched for the answer unsuccesfully so I'm posting it here. I'm was reading up on the uncertainty priciple when I ran into two phrases that I don't quite understand. They are <A²> and <A>². Am I too apply this as \int \psi^* A^2 \psi...
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