<p>And yeah pressure does not affect solubility only temperature. Hence why temperature is the only thing that can change the value of K constants.</p>
<p>Actually…I just looked it up and it says carbon dioxide is present in the greatest concentration in the atmosphere and contributes most to the natural acidity of rain water. Not to mention carbonic acid can dissocite to form H+ ions, which lowers the pH of water</p>
<p>I just remembered that for 6c I said:
“The reaction is zero order with respect to ethanol because the graph of [ethanol] vs time is a line.”
only to follow up with:
rate = k[ethanol]^1</p>
<p>lol failll</p>
<p>btw does anyone know what the new curve is (now that you don’t get penalized for incorrect MC) and what you generally need to get a 5?</p>
<p>That is true but like I said, if carbon dioxide every reacts with water it is highly unstable and will break apart. The acidity that carbonic acid does is practically constant, no matter how much carbon dioxide is in the atmosphere, the amount that does dissociate is a very small percentage. It is hard to imagine how much carbon dioxide is needed in the atmosphere to have an affect on pH contents around the world. As you probably know, Sulfur oxides and nitrogen oxides (except for sulfurous acid which is also an unstable acid) contribute to the global acidity around the world because of the strong acid formation.</p>
<p>My guess is it is around 40-45% but no one knows till college board grades all the tests and creates their “bell curve”.</p>
<p>Obviously, yes. But when my teacher discussed the frq, she listed that as a possible answer. Frankly, greenhouse gases and stuff seems more environmental science anyways, why waste a question on it</p>
<p>Yeah, we will see the possible responses when the scoring guidelines are released. But my guess its the same reason why they added those sometimes random questions on the reaction section of the free response…just a little chemistry trivia? lol</p>
<p>Yeah, acid rain is caused by sulphur dioxide, not carbon dioxide.</p>
<p>Carbon Dioxide makes rain slightly acidic but we don’t call that acid rain. All rain has a pH below 7 because of carbon dioxide in the atmosphere. This is not what we consider acid rain though. Oxides of sulfur and nitrogen are what we consider as acid rain causers. </p>
<p>I think what they were really looking for is something about CO2 and greenhouse effect/global warming, etc. Not acid rain</p>
<p>if i dont have an ice chart for the question that asked the [OH-] for a weak base, will i get a point off?</p>
<p>Firered, no i doubt you will get points off. As long as you showed that the Kb=x^2/[NH3] then you should be fine, collegeboard very rarely has taken points off for work like that in the past.</p>
<p>Does anybody know when they’ll release the scoring guides?</p>
<p>Not till july i think, when everything is graded.</p>
<p>
</p>
<p>I didn’t take the exam, but no, I don’t believe it is.</p>
<p>@sciencewiz I hope your right. I also showed what values x equaled, and that 0.100 - x is approximately the same as 0.100.</p>
<p>@firered Look at past Ka/Kb free response guidelines and see how they graded similar questions and compare it to what you showed. I think that might help you out the best</p>
<p>So what do you guys think the curve will be? Any predictions?</p>
<p>I think it’ll be larger than usual. CB talked about how the majority of students suck at rate law graphs last year, and what do you know, there was a FRQ on it. I suspect the curve will be slightly higher than last year (besides adjusting for no guessing penalty).</p>
<p>Higher than last year? I disagree; most people agree that this year’s AP exam was much harder than usual. I’ll be ****ed if the elimination of the guessing penalty screws everything up.</p>
<p>Does anyone know if we get to see the score division/bell curve and if so, when?</p>