<p>To be succint, I was wondering if anyone has chanced upon the answers to the 1978 FRQ for AP chemistry. I've tried a google search and wasn't too succesful. Thanks.</p>
<p>Hahaha. I read this question, laughed at its ridiculousness (1978?!), and then realized that I actually had the answers to the '78 exam! :P [url=<a href="http://online.cctt.org/physicslab/content/EssayAnswers/viewanswers_SQL.asp?pg=8%5DEnjoy.%5B/url">http://online.cctt.org/physicslab/content/EssayAnswers/viewanswers_SQL.asp?pg=8]Enjoy.[/url</a>]</p>
<p>Wasn't the OP talking about Chemistry though? Sorry, I'm confused.</p>
<p>Thanks for your help, but those are physics questions =/ </p>
<p>Thanks anyway!</p>
<p>Hahaha, damn it. Sorry, cannednish; not sure how it's possible to misread both a thread's title and the post itself. :o</p>
<p>And so the request reverts back to ridiculous. :D</p>
<p>Since no one has found the key, I might as well post the question...</p>
<p>9) The postulates of the Bohr model of the hydrogen atom can be stated as follows:</p>
<pre><code>(I) The electron can exist only in discrete states, each with a definite energy.
(II) The electron can exist only in certain circular orbits.
(III) The angular momentum of the electron is nh/2pi where n is any positive integer.
(IV) Radiation is emitted by the atom only when an electron makes a transition from a state of higher energy to one of lower energy.
</code></pre>
<p>(a) State whether each of these postulates is currently considered to be correct, according to the wave mechanical description of the hydrogen atom.</p>
<p>(b) Give the wave mechanical description that has replaced one of the postulates now considered to be incorrect.</p>
<p>I'm having some trouble with III a/b</p>
<p>I, III, and IV are correct. II is not correct.</p>
<p>The current wave mechancal model for the atom states that there are an integer number of wavelengths in every standing wave-a-ma-bobber.</p>
<p>So anyway, de Broglie's equation states l = h/(mv), so nl = nh/(mv) = 2pi(r).</p>
<p>Where: l = wavelength, v = velocity of electron, n = some positive integer, r = distance of electron from center, m = mass of electron.</p>
<p>Solve, get mvr = L = nh/2pi. Done. (From physics, angular momentum is given by mvr).</p>