Official June SATII Chemistry Thread

Test Preparation SAT Subject Test Preparation
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<p>The fact is, in that reaction the sodium ion is a spectator ion. The significance of that fact here is that the concentration of the sodium ion does not change in the reaction (since none of the ions will go into forming a substance of a different state of matter). We can then simply use the concentration of the sodium phosphate to get the concentration of sodium ions. Note that the final volume is 2 liters; in questions like these it is assumed that the molarities describe a ratio of X mol/1 L. </p>

<p>(0.10 mol/L Na3PO4)(1 L)(3 mol Na+/1 mol Na3PO4)(2 L) = 0.15 M</p>

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<p>hey guys! i got a 750 on the may test. do you think its worth retaking, or should i take math 2 for the first time instead?</p>

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<p>There’s no reason to retake a 750. Take math.</p>

<p>Or if you really, really don’t like the 750, why not take both?</p>

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<p>Is Barron’s grading scale accurate?</p>

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<p>Equal volume of 0.1M sodium phosphate and magnesium nitrate mixed together will immediately half the concentration of each due to the combined volume. I guess this is the part you’ve missed.</p>

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<p>Can anyone explain to me the correct answers to the following questions from the 1998 released SAT Chemistry Subject Test? I don’t get why those are the right answers.</p>

<h1>s 18, 41, 53, 60, 80, 81</h1>

<p>Here is the link:
<a href=“https://docs.google.com/viewer?a=v&pid=sites&srcid=aGJhLm5ldHxtaHV8Z3g6N2Q3YThiYmRlMGQxNDk3YQ[/url]”>https://docs.google.com/viewer?a=v&pid=sites&srcid=aGJhLm5ldHxtaHV8Z3g6N2Q3YThiYmRlMGQxNDk3YQ&lt;/a&gt;&lt;/p&gt;

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<ol>
<li><p>A. [H+] at 1.0 x 10^-7 indicates that the solution is neutral. If the concentration is higher than that, it means the solution is acidic, meaning the [H+] is > 1.0 x 10^-7, so it has to be an acid. Arrhenius acid is the only acidic option.</p></li>
<li><p>E. The electrons are just flowing; the copper isn’t reacting with the electrons, so nothing is gained or lost.</p></li>
<li><p>B. States of matter concept. If a solid absorbs enough heat, it goes from solid —> liquid —> gas (or even sublimes, w/e). The question states that it’s going from solid to gas, so heat has to be absorbed.</p></li>
<li><p>D. Pushing it further into the water puts more pressure on the gas, making it more soluble. Think about soda- you open the lid, and what happens? The gas escapes because you stopped putting pressure on it.</p></li>
</ol>

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<p>@Intelligentsia and billcsho
Thanks. Those types of silly mistakes really drag my score down.</p>

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<ol>
<li>The balanced reaction is:
Al2(C2O4)3 —> Al2O3 + 3CO + 3 CO2.</li>
</ol>

<p>So, the mole ratio is 3:3, or 1:1 (A)</p>

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<p>Thanks @lldm21 and @Renasani! I just need #60. Anyone?</p>

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<ol>
<li>B The amount of pressure exerted doesn’t change because if you plug in hydrogen in the ideal gas law equation PV=nRT we find that as long as Temperature, number of moles, and Volume doesn’t change then no change in pressure occurs. </li>
</ol>

<p>Or we could apply Ideal has law to the entire system of 6 moles and then apply Dalton’s laws of partial pressure.</p>

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<p>Taking this tomorrow! Subject test scores have gone from 710-760 in Barrons, but I’m aiming high! Good luck to everyone!</p>

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<p>Good luck to everyone…not that any of you will need it:) </p>

<p>Anyway, do you guys recommend studying today? Because, I was just gonna relax and take it easy, then read over the sparknotes Chem section before I go to bed at 10:30…
Good plan? Or no?</p>

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<p>“41. The balanced reaction is:
Al2(C2O4)3 —> Al2O3 + 3CO + 3 CO2.”</p>

<p>This is oxidation/reduction reaction, right? What steps do we need to do to balance this?</p>

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<p>@Intelligentsia;
We have to balance half reactions…that’s a combustion reaction too, but it does not have enough oxygen, hence, the CO instead of CO2.
Yeah…I don’t think this is redox, but I’m not sure.
EDIT: since no charges are present…I don’t think we have to balanace by charge.
Al tends to be (3+)
According to barron’s, it might be good to know that:
Ag (1+)
Cd (2+)
Zn (2+)
Al (3+)
Hg (2+)</p>

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<p>@athena I just took two released tests and made a 710 and 760. I’m still not completely confident in my ability to do well, but honestly as long as I get above a 700 I’m not retaking. Anywho - I haven’t really been studying so much as taking practice tests…</p>

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<p>Sorry again, but I need more help with understanding some things. Why does water boil at a lower temperature at higher altitudes but at increased pressures, boils faster?
I need help with the following questions: # 106 (why is it not T T CE?), 107, 115, 40, 43, 52 (how do you know it is Zn being oxidized and not Cu from the picture?), 59, 60.
This is the link:
<a href=“https://docs.google.com/viewer?a=v&pid=sites&srcid=aGJhLm5ldHxtaHV8Z3g6Mjc3YTcxYzlkM2I5MDliNw[/url]”>https://docs.google.com/viewer?a=v&pid=sites&srcid=aGJhLm5ldHxtaHV8Z3g6Mjc3YTcxYzlkM2I5MDliNw&lt;/a&gt;&lt;/p&gt;

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<p>How much harder is Barrons than the real test?</p>

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<p>@thelemonisinplay I agree. Anything equal to or above 700 and I’m happy. I studied a lot mostly because I didn’t take the AP course, I just took the honours course at my school.</p>

<p>Is it just me, or do you make a lot of stupid mistakes due to speed reading, or not thinking (“applying skills”), or math-ing wrong? (Mistakes as in, you go back to the question and you’re like…oh…) </p>

<p>[Apologies for somewhat incomprehensible grammar].</p>

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<p>@athena810 Yea. Those kinds of mistakes are really annoying. Make sure to read carefully for all the questions on test day.</p>