<p>Scottykid:
Zinc has a filled d orbital, so it’s valence electrons don’t move around. With other transition metals, unpaired electrons in the unfilled d orbital will jump around, releasing energy in the form of visible light.</p>
<p>sporty04:
(1.00mol Ni2+)(2mol e-/1mol Ni2+)(96,500 coulomb/1mol e-)(1sec/1amp)(1min/60sec)(1hr/60min) = 53.6 hours. I might be way off though.</p>
<p>1) How many electrons are transferred in the reaction represented by the balanced equation below?
2MnO4-(aq) + 10Br-(aq) + 16H+(aq) yields 2Mn2+ (aq) + 5Br2(aq) + 8 H2O (l) </p>
<p>i got 10 electrons</p>
<p>2) ZnSO4 i guess is colorless because everything else wasnt. i dont really know of any actual chemical way to explain it.</p>
<p>^^^@Bgdz810: i remember my teacher saying that, so i think youre right</p>
<p>Anyone know the curve/forumla for calculating your score?</p>
<p>Input would be appreciated = p</p>
<ol>
<li>The pH of .01 molar acetic acid (Ka = 1.8E-5) is closest to
A) 1
B) 2
C) 3
D) 7
E) 11</li>
</ol>
<p>Please someone explain how to do this without a calculator…</p>
<p>I know:</p>
<p>1.8E-5 = (x^2) / (.01-x)
but doing it without a calculator does not work for me. Tips?</p>
<p>Can anyone explain 3e from the 2009 FRQ?</p>
<p>You can ignore the -x in the denominator because it’s so small. So then it becomes
1.8E-5 = x^2 / 0.1</p>
<p>1.8E-6 = x^2</p>
<p>sqrt 1.8 ~ 1.3
sqrt 1E-6 ~ 1E-3</p>
<p>x = around 1.3E-3</p>
<p>You just have to use guesstimation and exponent rules for square rooting, lol.</p>
<p>So the pH would be around 3.</p>
<p>Does anyone know if Barrons practice tests are harder, easier, or accurate compared to the actual AP test?</p>
<p>I am pretty sure the Barrons practice tests are more difficult compared to the actual test.</p>
<p>1) How many electrons are transferred in the reaction represented by the balanced equation below?
2MnO4-(aq) + 10Br-(aq) + 16H+(aq) yields 2Mn2+ (aq) + 5Br2(aq) + 8 H2O (l) </p>
<p>i got 4… how did you get 10?</p>
<p>I am also going to go out on a limb and say that I have not seen an electrolysis question on the previous years of AP exams so that could be another FRQ.</p>
<p>Bgdz810 - sorry but the answer is 193,000.</p>
<p>and FalconPAWNCH, can you show me the steps you took for this problem (sorry to bother!)</p>
<p>Also…random questions
<ol>
<li>When a solution is formed by adding some methanol, CH3OH, to water, processes that are endothermic include which of the following?
I. Methanol molecules move water molecules apart as the methanol goes into solutin.
II. Water Molecules move methanol molecuels apart as the methanol goes into solution.
III. Intermolecular attractions form between molecules of water and methanol as methanol goes into solution.
the answer is I and II only but I don’t know what the heck this question is talking about. lol</li>
</ol>
<p>In which of the following processes are covalent bonds broken?
a. solid silver melts.
b. solid potassium chloride melts.
c. solid carbon (graphite) sublimes. ----answer (why though?)
d. solid iodine sublimes.
e. glucose disolves in water.</p>
<p>
</p>
<p>Good… because I am getting decimated on this first practice test. I got all the first 14 right but then from there I’m missing quite a few.</p>
<p>Note: I got ~65% MC right on the 2 mock exams i took, and i can agree that barons is harder</p>
<p>@sporty</p>
<p>A volumetric flask is just a flask that is accurate for measuring (as opposed to say, a Erlenmyer flask, which is not). The flask is better than the pipet because it’s closer to the volume that you are measuring (.1L), which is what you are looking for in good equipment to measure a particular volume.</p>
<p>@sporty again</p>
<p>Your third question:</p>
<p>Carbon is a covalent network, so as a solid it is held together by covalent bonds, which must be broken as it becomes a gas.</p>
<p>Could I please get the answers to the 2008 audit for Chemistry?</p>
<p>Thanks a ton. You’ll really help me out.</p>
<p>sporty04: It’s 193,000 seconds, I just converted it to hours for no particular reason. So if you wanted seconds, then the last 2 steps were unnecessary.
As for the volumetric flask, it’s a piece of glassware with a very precise marking of whatever volume it’s intended for. The top of it is also very narrow, so that you can essentially plug it to agitate the solid until it dissolves. With the pipet, tiny bits of water are left on the pipet walls when you transfer the water to another container… I think.</p>
<p>I’ve only been getting about 30-45/75 right on the Barrons practice. I only need to get a 3 so I shouldn’t have trouble.</p>
<p>Last question…when writing net ionics, where can you put the charges? Only on the elements that were in the aq solution, not on solids? And do you carry down the coefficients from the balanced equations?</p>
<p>I have to learn everything about acid-base chemistry tonight.</p>
<p>Can anyone tell me what getting 57-60% (my average at the moment) right on the multiple choice will get me on the AP? Will it get me a 4 even if I fail the FR part hard? </p>
<p>Also, can someone list all the common colors for elements you usually see on the AP?</p>
<p>Good luck QuantumLipids. Acid/Base is not the easiest, IMO. Of course, it’s not the worst either. What do people think is the worst? I’m not sure…</p>