The AP Chemistry Study Thread

<p>I've seen this question before...I know the answer, but yet I have no clue how to do it. It's one of the questions I got wrong on the practice MC test I took.</p>

<p>Quick Question: What's is the raw score total to get a 5 and a 4?</p>

<p>Is it something like 107-160 = 5 & 83-107 = 4?</p>

<p>Scareya in the spark notes book >120 is a 5. I am not sure. asked my teacher so many times~ can't answer. we were going over the multiple choice and us students had more clear ways to solve the problems than him.</p>

<p>The answer is C; it's on the 1999 MC.</p>

<p>chunlin you are right. give us a Q</p>

<p>yeah, somebody post a question.</p>

<p>AP QUESTION: At the triple point (pure substance):</p>

<p>(A) The vapor pressure of the solid phase always equals the vapor pressure of the liquid phase.
(B) The temperature is always 0.01 K lower than the normal melting point.
(C) The liquid and gas phases of the substance always have the same density
(D) the solid phase always melts if the pressure increases at constant temperature
(E) The liquid phase always vaporizes if the pressure increases at constant temperature.</p>

<p>is it c? just guessing ;D</p>

<p>a) krazy head</p>

<p>4got to post a question in my last response...
The safest and most effective emergency procedure to treat an acid splach on skin is to do which of the following?
a) Dry affected area with towels
b) Sprinkle affected area with powdered Sodium Sulfate (s)
c) Flush affected area with H2O and dilute with NaOH sol'n
d) Flush affected area with H2O and dilute with NaHCO3 sol'n
e) Flush affected area with H2O and dilute w/ vinegar sol'n</p>

<p>Explain answer since its a theory question.</p>

<p>Also I have a question for myself. Can someone specify Lewis Acid/Base and Bronsted Lowry Acid/Base...make sure you're right lol since they're confusing</p>

<p>Thanks</p>

<p>D. I think; i'm pretty sure you would counteract the acid with baking soda which is sodium bicarbonate.</p>

<p>A lewis acid is an electron pair acceptor; lewis base is electron pair donor.
Arhennius Acid gives off H+ ions in solution while Arhennius base gives off OH- ions in solution.
Bronsted acid is a proton donor, while arhennius base isa proton acceptor. </p>

<p>How does electronegativity, electron affinity, ionization energy change as the atomic number changes? Describe using the periodic table as a model</p>

<p>D iam sure</p>

<p>d. i think it is also from the 99 released exam</p>

<p>By the way: it's right here
<a href="http://dbhs.wvusd.k12.ca.us/webdocs/AdvancedPlacementChemistry/AP-Chem-Test-Archive/AP-MC99.html%5B/url%5D"&gt;http://dbhs.wvusd.k12.ca.us/webdocs/AdvancedPlacementChemistry/AP-Chem-Test-Archive/AP-MC99.html&lt;/a&gt;&lt;/p>

<p>How does electronegativity, electron affinity, ionization energy change as the atomic number changes? Describe using the periodic table as a model:
All of those increase as we move from left to right on a periodic table. However, those decrease as we move down in a period. it has to do with the shielding effect</p>

<p>thanks chunlin</p>

<p>question: whats the best way to prep for the lab essay question? practice? we really didnt do any lab for our class....i feel really unprepared for this test.</p>

<p>looeypie~ I read that the cliffnotes AP Chem has a really good review for the lab. I think you should buy that</p>

<p>ok tthanks!</p>

<p>What is considered good (5 worthy) score on the MC? I know it depends on FR too but whats a good score/range for a 5?</p>

<p>Either range of ?'s right or score after subtracting .25(#wrong).</p>

<p>Questions continuing:</p>

<p>NH3 + HOH <--> NH4+ + OH-</p>

<p>1) determine the pH of .0180 M NH3</p>

<p>2) determine the value of the base ionization constant for NH3</p>

<p>3) In an experiment a 20.0 mL sample of a .0180 M NH3 was placed in a flask and titrated to equivalence point and byeond using .0120M HCL.</p>

<p>Part 3 i) Determine volume of .0120 M HCL that was added to reach equivalence</p>

<p>Part 3 ii) Determine the pH of the solution in the flask after a total fo 15.0 mL of .0120M HCL was added</p>

<p>Part 3 iii) Determine the pH of the solution in the flask after a total of 40.0 mL of .0120M HCl was added</p>

<p>If you're curious, this is from the 1999 released exam. Not too bad.</p>