<p>umm, omgpie on number two your mass only included water and not the urea</p>
<p>^^ that would be cool haha
I’m just guessing how many each is worth lol</p>
<p>For the rate law question explanation could you also have said that termolecular and greater collisions are extremely rare?</p>
<p>haha does anyone wanna guess a curve also?</p>
<p>im guessing 75 pts of MC, 75 pts for FRQ combined to 150</p>
<p>100/150 = 5
80/150 = 4</p>
<p>@hobbithill: yea – u could have said that the whole thing would have been 6th order which is impossible for a single step reaction</p>
<p>Is the answer for 2b exothermic or endothermic? I said it was exothermic, but wasn’t sure.</p>
<p>endothermic because the temperature of the water went down which means the reaction absorbed energy</p>
<p>argh, i put exo.</p>
<p>What is the answer to 2f?</p>
<p>Student performs third trial with 5C urea – what happens to dH?</p>
<p>For 2f, I said that delta H would increase because it would take more heat to dissolve the urea due to its cold temperature.</p>
<p>How do you know urea doesnt dissolve fully at 5C?</p>
<p>It is also endothermic because we know bonds are being broken.</p>
<p>anyone else for 2f?</p>
<p>Zn2+'s electron config is: 1s2 2s2 2p6 3s2 3p6 3d8 right?</p>
<p>Also…Zn2+ definitely has the greater ionization energy. You’ve already removed 2 electrons, so the protons are holding on to the electrons with more power/force (greater effective nuclear charge). </p>
<p>In addition, cell voltage increases for 6g. Reasoning: Le Chatelier’s Principle and then nernst equation. If [prod] is less than 1 but [react] stays at 1, logQ is negative, negative and negative makes positive, making Ecell > E0 cell.</p>
<p>2f: Using a lower temperature of urea will increase dH (make it more positive) </p>
<p>My reasoning was that the lower temperature would lower the water temperature, and then the reaction will lower the water temperature EVEN further. Therefore, the final temperature will be lower, making it seem like the reaction absorbed more energy, increasing dH.</p>
<p>@miheonigirisan, if you look up urea on Wikipedia, it says that the solubility of urea in water decreases with temperature (733g/100mL @ 100 degrees C, 108g/100mL @ 20 degrees C). So wouldn’t more heat be required to dissolve urea when it is cold? Did anyone else say the same thing as I did for 2f?</p>
<p>Delta H definitely increases.</p>
<p>@ninmage621: but isnt the intial temperature lowered as well?</p>
<p>dammit, wats the curve for a 5? lmao</p>
<p>No the initial temperature is that of the water itself, before the urea is put in.</p>