June SAT: Chemistry Post-Test Discussion

<p>yeah , got that wrong… was the one about how hCl and AgNO3 forms Agcl ppt & because hcl is a strong acid T,T or T,T,CE?</p>

<p>I thought the hcl and agno3 one was T, T. What did you guys think about the graph with the energies of reactants of products and reactants? Exo or Endo???</p>

<p>The graph showed an exothermic reaction because the energy of the reactants located higher than the products, indicating that energy was lost during the reaction. This loss of energy means that the reaction is exothermic. Endothermic would be the backwards graph of it.</p>

<p>ok. good that’s what i put :)</p>

<p>and just checking, but it’s been decided that there were 4 CE’s, right?</p>

<p>I’m not even going to attempt to guess my score. :)</p>

<p>I got 8 for one balancing problem, and 4 for HCO3- or whatever. Hoping for 750+. Omitted 6 and got a few wrong.</p>

<p>another galaxy do u remember the entire balancing problem</p>

<p>was 8 choice E for that question?</p>

<p>For the HCO3 question, I got 2.</p>

<p>i got 2 for that also i think</p>

<p>^ what was the reaction problem with 8 as teh answer</p>

<p>I think it was 8O2 but I’m not really sure.</p>

<p>another galaxy do u remeber more of the reactants or products</p>

<p>H2O was in there somewhere</p>

<p>So far I skipped 3 and got 3 wrong. What u think is gonna be my score?</p>

<p>The 8 was the coefficient for the equation with O2 as a reactant. I think a raw score of -7 will give you 770-790.</p>

<p>For the balancing question, I know the balanced equation is:</p>

<p>2CaCO3 + H2O+ CO2 -> Ca2+ + 2HCO3-</p>

<p>But i am really confused because both C in CO2 and CaCO3 has an oxidation state of +4, and both C is being oxidized to +5 (C in HCO3- is +5); C is oxidized and nothing is being reduced! How’s that possible?</p>

<p>The reaction is:</p>

<p>…P4S3+…O2 -> …P2O5 + …SO2</p>

<p>and so the balanced equation is</p>

<p>P4S3 + 8 O2 -> 2 P2O5 + 3 SO2</p>

<p>After looking through the ENTIRE 19 page thread, I have 3 wrong (which is good right, because it’s still an 800?)</p>

<p>What I got wrong:
-Put NaAt instead of NaF (this is the only question in the entire test I did not know, I thought higher mass = higher melting point)
-Put Oxidation instead of neutralization on acid rain/limestone question (can someone confirm that it is actually neutralization, b/c I read somewhere that acid rain causes oxidation)
-Put covalent bonding for Nitrogen gas instead of dispersion forces (can someone confirm that dispersion forces is the answer?)</p>

<p>Also, one question you guys did not mention is:
Which property is NOT a function of temperature when volume is kept constant?
-Pressure
-Deviate behavior from ideal gas
-TOTAL energy of gas
-density
-some other answer that was obviously wrong</p>

<p>I narrowed it down to the behavior answer and the total energy of the gas.
I put total energy of the gas because the total energy under the curve always remains constant, right? Temperature only increases the AVERAGE kinetic energy, not the total energy. Besides, there is an equation out there relating temperature to deviation from ideal gas behavior.</p>

<p>Can someone confirm my answer on this Q?</p>

<p>By the way… Al2S3, anyone?</p>

<p>I’m so mad that I made stupid mistakes. Ugh</p>