Chemistry Olympiad 2013!

Pre-College Issues High School Life
201

<p>@huehuehue32</p>

<p>dH = dE + PdV
dH - dE = PdV</p>

<p>So now we know that the answer is PdV … which is -4.6 * 10^-3 L<em>atm</em>mol^-1</p>

<p>What we want, however, is J<em>mol^-1, so you need to convert L</em>atm to J. We take the two R factors given, 8.314 J<em>mol^-1</em>K^-1 and 0.0821 L<em>atm</em>mol^-1<em>K^-1 and take the first over the second, giving you 101.3 J</em>L^-1<em>atm^-1. We then multiply this by the PdV, so -4.6 * 10^-3 L</em>atm<em>mol^-1 * 101.3 J</em>L^-1<em>atm^-1 and including units this yields -4.7 * 10^-1 J</em>mol^-1, so the answer is A.</p>

<p>That paragraph is so hard to read… oh well.</p>

202

<p>When is local MC released?</p>

203

<p>Finally got results back today haha, a little late. Qualified though, with a 57!</p>

204

<p>Lol yeah, we got our results on the same day we took it.</p>

205

<p>For those of you guys taking the NCO and aiming for top 50/ 150, for how long have you guys prepped/ been taking chemistry?</p>

206

<p>heyhey2</p>

<p>the key is to make your swagsack large enough to overcome any obstacle</p>

207

<p>Did you guys feel the local exam this year was easier or more difficult than the exams from previous years?</p>

208

<p>Slightly easier because barely any buffer/equilibrium questions came up. Overall about the same level of difficulty. </p>

<p>Now I’m just worried about the national exam…</p>

209

<p>is it possible to get top 150 if you get ~45 on the MC 80% on the free response, but bomb the lab part?</p>

210

<p>top 150 is only based on multiple choice score, which typically means 45+</p>

211

<p>Hi guys, is there any formula for calculating one’s final scores?</p>

<p>And also, what score would be appropriate to make camp??</p>

212

<p>Today was the only day to take it, right? Can we discuss it yet?</p>

213

<p>The last day to take it is Monday, 4/15. Please do not discuss until then!</p>

214

<p>Nope, I took it yesterday. And yeah I think the last day is Sunday.</p>

215

<p>When will we get our rankings usually?</p>

216

<p>Last day is Monday. Top 20 are called in first week of May, 50 and 150 are announced sometime after that.</p>

<p>Last day to take it is the 15th - I’m taking it tomorrow, good luck to everyone else!</p>

217

<p>3 Chainz I don’t have enough posts to PM.</p>

218

<p>Well how was the difficultly compared to past years’ tests?</p>

219

<p>I didn’t do USACHO last year. Based on the practice tests, I thought the FRQ this year was def harder this year. Multiple choice I thought was about the same.</p>

220

<p>Just took it. 5 hours of chemistry, woo! I was actually pleasantly surprised by the MC and lab portions. But the free response was death.</p>