<p>any ideas on the curve? basically just learned all of ap chem within the past 2 days soo…here’s hoping it won’t be like AP bio last year haha</p>
<p>does anyone else think the online barrons frq are much harder than the official tests frq?</p>
<p>For #60, there’s originally 1 atm of COCl2, treat it as equilibrium problem and use ‘ice’ method of some sort:
COCl2 CO Cl2 Becomes 1 + x = 1.2atm, x=.2atm then Kp=(co)(cl2)/(COCl2) = (.2)(.2)/.8 = .05
1atm 0 0
1-x +x +x</p>
<p>@ChemCramyea yeah it is precipitation. OH- + H+ --> H20 is the neutralization reaction. </p>
<p>@PersianPwr you need to do an ICE diagram to find ‘x’ and then plug it into the Kp formula</p>
<p>@hannaners I’m guessing like a 66%?</p>
<p>Do we need to know buffer calculations and stuff? Like the 2011 FRQ #1.</p>
<p>Can someone explain 10 on the barrons online test mc? i feel like it should be really easy but i got it wrong</p>
<p>Can someone also explain 48 and 49 on the practice mc? I thought that the smaller the Ka value the weaker the acid?</p>
<p>@10bio10 remember that the higher the pH the weaker the acid. I got stuck on that too the first time hahah</p>
<p>10bio: thats true , did u do the same thing i did and select acid 2 , if so , remember that the weaker an acid the higher the ph so the answer is acid 1</p>
<p>Do we need to know how to calculate change in pH from mixing solutions and buffers?</p>
<p>Whoops 
I was so frustrated trying to figure that one out haha and that solves like the rest of my problems with that section. </p>
<p>I have a question: why wouldnt collegeboard want teachers to release the practice exam to their students?</p>
<p>does anyone know how to read PES graphs?</p>
<p>@mathpop yes check out PES - YouTube</p>
<p>@mathpop Is that an important part? bc I don’t know anything about them :(( </p>
<p>Is anyone else using the Demmin review guide? I’m slightly nervous because I have a B in the Chemistry class this semester (I suck at second semester chem), but our teacher made us a deal that a 5 is an A. I just wanted to see what other people thought about that review book, and how it might compare to the exam</p>
<p>@graceann if my teacher went over it , it definitely is because she didnt go over much</p>
<p>@mathpop you should try Bozeman science. He goes over that in one of the videos. </p>
<p>Yes on a PES graph there is a separate peak corresponding to each sub level and the height is the number of electrons in that sub level. The x axis is the energy required to remove electrons. Example: sodium has 4 peaks a 1s 2s 2p and 3s peak. The 1s requires the most energy then 2s then 2p… The peaks would shave heights relative to the electrons in that sub level so for Na 2:2:6:1
Does that make any sense?</p>