<p>I did the practice test by college board and I have some question... can somebody please help me?? @@</p>
<p>Which of the following does NOT react with a dilute H2SO4 solution?</p>
<p>a) NaNO3 b) Na2S c) Na3PO4 d) Na2CO3 e) NaOH</p>
<p>the answer is A and I have no idea why...</p>
<p>and here's another question:</p>
<p>To determine whether a water solution of Na2S2O3 at room temperature is supersaturated, one can...</p>
<p>a) heat the solution to its boiling point
b) add water to the solution
c) add a crystal of Na2S2O3 to the solution
d) acidify the solution
e) cool the solution to its freezing point</p>
<p>the answer is c, but again, I don't know why. I mean, how can adding more prove the solution is supersaturated??</p>
<p>first one I don't know. Second one, adding a crystal to a supersaturated solution would cause anything past the level of saturation to fall out of the solution, so that's true, it is C.</p>
<p>ok for the first one H2SO4 is a strong acid. It will lose its first H really easily and won't want to pick up any. So when it will donate H, the conjugate bases of the acids will pick it up and form acid. But conjugate bases of strong acids don't like to pick up H so the answer is A. NaNO3. NO3 is the conjugate base of a strong acid.</p>
<p>why is it that conjugate bases don't like to pick up H...is it because strong acids completely dissociate, so when adding an H it would just remain unreacted? Around how many questions involving strong acids/bases can we expect on the test?</p>
<p>not that. conjugate bases of strong acids don't like to pick up H because they dissassociate completely.
Like the conjugate base of HCN, which is CN will definitely pick of H</p>
<p>Hrm. I might be totally wrong, but I thought that the reason NaNO3 won't react with H2SO4 is because, if you mix them together, you have NA+, NO3-, 2H+, and SO4 -2, and NA+ and NO3- are always soluble, and SO4-2 is almost always soluble (except when combining with Ba, Ca, and Strontium)... so you just get a bunch of ions floating in a solution, so there's no reaction. The other options are either neutralization or form insoluble compounds (thus reacting)</p>
<p>That's also true, but the reasoning behind the fact that they're always soluble is the strong acid/conjugate base that sristi described</p>
<p>i thought strong acids dont have congugate bases..?</p>
<p>the conjugate base of a strong acid is neutral</p>
<p>I think in my Barron's book the answer to the first one was because NaNO3 requires heat to react. I dont' know how you would know that, though.</p>
<p>I have a question, what SAT material is on the tests that isn't in Honors Chemistry class? </p>
<p>So far, I know
-Pi and Stigma Bonds
-KPA charts</p>
<p>Pi and Sigma bonds are on the test?</p>
<p>pi and sigma bonds aren't on the test........</p>
<p>what is KPA? is that like Equilibrium and stuff? if so, that's on there.</p>
<p>kilopascals? That's what I thought kpa was...</p>
<p>Maybe they mean pKa...</p>
<p>pKa...yes that would make sense</p>
<p>opps yeah Pka using equilibrium charts and -[log] or something</p>
<p>looking through the review book for the test it seems like there's equilibrium which you don't learn much about in chem honors.
that's where all the Ka, Kb, Kpa, Ksp, Keq, etc. come from.
they're basically just values for acid equilibrium constant, base equilibrium constant, solubility constant etc.
i'm not sure how in depth you need to know though, because you can do A LOT with equilibrium and equilibrium constants.
i also think there's stuff on titrations which is covered very well.
i like how little help i provided.
sorry.</p>
<p>i just found out the answer to the 1st question.. the reason the answer is a NaNO3 is that both group 1 elements and nitrates are unreactive in aqueous solutions</p>