<p>I wouldn’t worry about orgo at this point, just review some basic functional groups and naming and you are pretty much set. But it is a minor topic.</p>
<p>dont review for ochem rofl. its useless at this point.
just make sure to remember your formulas and you should be fine.</p>
<p>So I just took the test in the PR book getting a 49 out of 75. The book first off said I would probably get a 5 for that score. Is the practice test in PR similar to the actual test, or is it easier/harder?</p>
<p>^thats about right. take one of the released exams.</p>
<p>Can anyone explain the answers to these questions for me? Idk why the answers are what they are.</p>
<p>1.) If the temperature of an (aq) solution of NaCl is increased from 20C to 90C, which of the following statements is true?
a. the density remains unchanged
b. the molarity of the solution remains unchanged
c. the molality of the solution remains unchanged
d. the mole fraction of solute decreases
e. the mole fraction of solute increase
**the answer is C</p>
<p>2.) which of the following gases deviates most from ideal behavior?
a. SO2
b. Ne
c. CH4
d. N2
e. H2
**** answer is A</p>
<p>ALSO (sorry for so many questions haha!) how do you do this problem easily without a calculator?
3.) if 87.5% of a sample of pure 131-Iodine decays in 24 days, what is the half-life of 131-Iodine?</p>
<p>Where can I get a released exam?</p>
<p>jacmoo-</p>
<p>raising the temperature of a solution has no affect on the mass of the solute or the solvent. thus, molality is unchanged.</p>
<ol>
<li>I forget exactly why, but SO2 has the largest molar mass, and the larger a gases’ molar mass, the more likely it will deviate from ideal behavior.</li>
</ol>
<p>@jacmoo,</p>
<p>3) 87.5% = 50% + 25% +12.5% = 3 half lives = 24 days…so, 1 half life is 8 days.</p>
<p>Well … it’s crunch time.</p>
<p>wait what does 56 out of 75 mean for me in order to get a 4? like what should i get in frq?</p>
<p>I took a practice test and I got 56/75, but I answered all of them so 51 and a 29.5 out of 54 of the FRQs. I kinda did poorly on the FRQs, but is that in the 4/5 range?</p>
<p>why does the volume change and the mass doesnt? (the molarity changes but the molality doesnt)</p>
<p>and thanks everyone!
your explanations helped a lot :)</p>
<p>jacmoo// molarity is subject to change because it is measured by number of moles divided by the volume, and volume may fluctuate as temperature changes. therefore it is not constant 
Molality… well… conservation of mass explains everything… because it’s moles of solute over kgs of solvent.</p>
<p>Another question for practicing question 4. </p>
<p>Excess nitric acid is added to solid calcium carbonate. (Remember, NET IONIC equation)</p>
<p>Can someone briefly go over bond order and resonance structures for me please? Like, calculating bond order, etc.</p>
<p>Example> which will have a shorter bond and why, Nitrite ion or Nitrate ion?</p>
<p>HNO3 + Ca(CO3) -> HCO3 + CaNO3
H + NO3 + Ca(CO3) -> HCo3 + Ca + No3
H + CaCO3 -> HCO3 +Ca</p>
<p>@nonexistent:</p>
<p>H+ + CaC03 –> Ca2+ + HCO3</p>
<p>You guys, don’t forget that H2CO3 ALWAYS breaks down into CO2 and H2O.</p>
<p>i dont understand, nonexistant.</p>