<p>Is the anode always the electrode on the right?
I’m going through a free-response and it asked to identify which species was at the anode. I don’t understand how to choose between two reactants?</p>
<p>Anode I believe is the one being oxidized, so it is losing electrons so the direction of electrons should be away from it. From most of what I’ve seen, you have to draw in electron flow, so by looking at the equation things (back of periodic table of ref sheet with E in volts) its the one that you flip?</p>
<p>Kevin, the way I look at it is you want to have a positive value of E, so you have to flip the more negative one so that when you add the values it is positive. This is for spontaneous reactions, where E is positive. It is the opposite for non spontaneous.</p>
<p>Someone correct me if Im wrong.</p>
<p>Also, I know thse are sort of old but here are some calc ab/bc mc exams if people are still looking for some.</p>
<p><a href=“http://asmsa.org/math/marizza/Calculus/APTEST/ap04_calcmc_collection_final_4_12_05.pdf[/url]”>http://asmsa.org/math/marizza/Calculus/APTEST/ap04_calcmc_collection_final_4_12_05.pdf</a></p>
<p>Also, skateme, you are still looking for AP world PM me.</p>
<p>Monarchy is right. You can’t call it by a glance, you have to first flip/balance the half rxns and find the cell potential before you know which is the anode/cathode. Remember standard potentials are NOT multiplied when balancing an equation.</p>
<p>So, if I have an electrochemical cell, we know it will be spontaneous, and thus I would need to find which combination would make a positive E.
And the opposite for a galvanic, since those are always non-spontaneous?</p>
<p>Pretty sure its the other way around, correct me if I’m wrong though. Galvanic-spontaneous: positve E, Electrochemical: nonspontaneous (needs a current)-negative E.</p>
<p>@jarredp93: That’s correct.
@Abrayo: The anode is for the oxidation reaction and the cathode is for the reduction reaction. If you look at the first letters of those four key words, you would notice that “anode” and “oxidation” all start with vowels while “cathode” and “reduction” start with consonants. It’s a good way to remember them.</p>
<p>Galvanic cells occur spontaneously if a salt bridge is present. Electrolytic cells need to overcome the negative electric potential with a battery so that the resulting E is positive and spontaneous.</p>
<p>Hey, does everyone know about this guy </p>
<p>[Khan</a> Academy](<a href=“Khan Academy | Free Online Courses, Lessons & Practice”>Khan Academy | Free Online Courses, Lessons & Practice)</p>
<p>If you don’t understand something, try watching one of his videos, he explains it well.</p>
<p>Where’s the answer to that 2004 exam? D: I downloaded that rar file and it didn’t have the answers.</p>
<p>Guys, if you were given a set of diatomic molecules such as:</p>
<p>Br2, I2, N2, Cl2, H2, O2, F2…how would you know which one has the lowest london dispertion force?</p>
<p>I thought it would the one with the smallest bond length? 
I need to improve my multiple choice by 7 to get in the 5 range? I scored a 48 raw on the MC of the 2008 AP Chemistry exam…do you think it’s possible to increase that to 55 (5 range)? And what free-response percentage would I need? I scored about 65% on the 2008 free-response.</p>
<p>Dispersion** sorry</p>
<p>I’d assume you’d look for a higher nuclear charge. More protons means larger induced dipoles (London). The electron cloud is more polarizable if it has a larger atomic weight, and therefore more protons.</p>
<p>And 48 is already a 5 range. You need to work on getting your FRQ scores up. Check this site out:</p>
<p>[AP</a> Pass - AP Chemistry Calculator](<a href=“http://appass.com/calculators/chemistry]AP”>AP Chemistry Test Score Calculator - AP Pass)</p>
<p>It’s been corrected for the scoring changes.</p>
<p>@skateme,
yeah, my friend also showed me that site. If the minimum raw score for 5 is 100 (67 %), I’d be so happy. But when we took a practice test as a class, our ap chem teacher told us that the new minimum for a 5 would be around 75 percent, which is a raw score of about 113, because you can guess on every question. I mean, 75 percent, if you think about it, is really hard to get, so I just hope that the site is correct.</p>
<p>whs, it is not the smallest bond length.</p>
<p>It is the one with the greatest size. This is because the electrons are more polarizable the farther they are away from the nucleus, plus more electrons means a greater chance for a momentary dipole.</p>
<p>What are you guys doing for your last week of cramming? I haven’t gotten a chance to take a practice exam yet maybe I’ll get to it on the weekend. But yeah I’m basically reviewing the early topics in PR and then I’m going to cram the harder topics at the end of the week. </p>
<p>good luck guys!</p>
<p>G0DZILLA, I was planning on doing the exact same thing. I am SO nervous for this test, not to mention it’s my first real AP exam.</p>
<p>My class is wasting 90 min for the next 3 days doing demonstrations and going over FRQs we were assigned for spring break. The only review of concepts is afterschool for 25-45 min until Friday.</p>
<p>Whoopie.</p>