<p>**** i put 80 seconds…</p>
<p>Me too. **** me.</p>
<p>What was the answer to the second to last question? It said something like which will produce 2 moles of hydrogen gas? The choices were like Mg, Ca, Ba etc. And fir the last one was it BeF2?</p>
<p>^ think it was Al</p>
<p>yea i got Bef2</p>
<p>yeah i got Al and Bef2</p>
<p>I agree with both of those.</p>
<p>Anyone up for some compilation?</p>
<p>For the A–>B T/F question, I will quote from Barron’s SAT II Chemistry:
(Section talking about reaction rates with catalysts)
"…catalyst provides an alternative pathway by which the reaction can proceed and in which the activation energy is lower. it thus increases the rate at which the reaction comes to completion or to equilibrium.</p>
<p>(Activation Energy section)
“Often a reaction rate may be increased or decreased by affecting the activation energy”</p>
<p>EDIT: Yes, the answers are Al and BeF2</p>
<p>Hope this helps.</p>
<p>My two questions:
- What was the answer to the T/F question about collecting H2S with water displacement?
- What was the answer to the T/F question about petroleum?</p>
<p>For the activation energy graph/reaction rates, I was debating over it and I decided that the rates could not be determined from the graph.</p>
<p>The arrhenius equation did depend on activation energy, but the constant A is different for different reactions.</p>
<p>For example,
Suppose the reaction “A–>B” is H2O (g) –> H2O (l)</p>
<p>At 150 degrees C and 1 atm, the reaction would be faster in the reverse direction.</p>
<p>At 50 degrees C and 1 atm, the reaction would be faster in the forward direction.</p>
<p>However, at both temperatures, the Ea is higher for the reverse than for the forward.</p>
<p>The Arrhenius equation simply tells you how fast the rate constant grows with respect to temperature, not how big the rate constant actually is.</p>
<p>i remeber it was True for the petroleum thing, since you can seperate through its diffence in boiling points.</p>
<ol>
<li>i skipped.</li>
<li>i put ttce, a guess tho</li>
</ol>
<p>yeah,
2. TTCE
im pretty sure too</p>
<p>Thanks guys. Yeah, I just looked it up in my Barron’s book. Barely remembered it when i took the test though 
Does anyone else know about the H2S thing?</p>
<p>Also, what’s considered a good score for SAT II Chemistry? I’m absolutely sure I got at least a 770, but should I retake it to get the 800? Does an 800 make a comparable difference than a 770-790?</p>
<p>jeez, why arent people happy with high 700s ? I just need to get above a 720 so i can exempt chem 1 at GeorgiaTech if I dont get a 5.</p>
<p>How many questions missed is a 700 flat? I answered them all.</p>
<p>I agree with XRCatD now. The Arrhenius equation draws on both A and Ea. A can vary depending on the reaction; Ea alone does not influence the speed of reaction.</p>
<p>Fe+3 + __OH- -> ?</p>
<p>Shouldn’t it be Fe(OH)6^-3 due to complex ions? I saw someone post Fe(OH)3 earlier.</p>
<p>^i don’t think so…</p>
<p>I think it was 3 for OH-</p>
<p>What is the rate of decomp thing 5 seconds?
I put 5 then changed it to 80 :(</p>