<ol>
<li><p>Strength of the those acids are HF<hcl<hbr<hi size=“” is=“” hf<hcl<hbr<hi=“” bond=“” strength=“” but=“” polarity=“” hf=“”>HCl>HBr>HI</hcl<hbr<hi></p></li>
<li><p>I am not entirely sure, but my best guess is that the only way to ionize a liquid without putting it into solution is to place a magnet in it. Remember, it is KNO3 in KNO3 not water.</p></li>
</ol>
<p>thanks a lot for your explanation:) so if it were in water, stirring and adding heat would cause more solute to dissolve?</p>
<p>That is correct. I am glad I can help.</p>
<p>What is the maximum number of moles of PbSO4 that must be used to prepare 1L of saturated PbSO4 solution at 25 degrees Celcius…(Ksp at 25 degrees Celcius of PbSO4 is 1*10^-8)</p>
<p>The answer is 1*10^-4.</p>
<p>I would be glad if anyone could explain to me how to go about the question.</p>
<p>Thanks in advance.</p>
<p>…PbSO4------->Pb^2+ SO4^2-
I…some # (s)…0…0
C …-s …+s…+s…(the dots are for formatting)
E…total-s…0+s…0+s</p>
<p>The Ksp equation would be:
A----> nB + xC
Ksp= **^n [C]^x</p>
<p>so…</p>
<p>Ksp= [Pb^2] [SO4^2-]
1<em>10^-8= (s)(s)
1</em>10^-8= s^2
s= √1<em>10^-8
s=1</em>10^-4</p>
<p>anonymous1993,</p>
<p>if the mol ratios are 1:1 does it mean that the molarity are also a ratio of 1:1 (if they have the same volume)?
How about in this question:
2H2O–>2H2+O2
The volume of of water vapor required to produce 44.8L of oxygen by the above reaction is:
89.6L</p>
<p>Here they just multiplied 44.8 by 2. Why can you do that? Can you please explain to me in depth because I don’t understand why they can do stoic using volume when it should be moles?</p>
<p>Yes</p>
<h2>(Molarity is only with solutions. The question below is with gasses.)</h2>
<p>Normally you would not be able to do this, but both the reactant and the product are gasses. For gasses, the conversion from one mole of water would be as following:
(Remember: 1 mole of a gas always fills out a volume of 24L)
n L H2O…1 mol of H2O gas…1 mol O2…24 L O2
----------X---------------------X-------------X--------------= 44.8 L O2
…1…24L H2O gas…2 mol H20…1 mole O2</p>
<p>Basically 24n/(24(2))=44.8
n/2=44.8
n (number of liters of H20 gas)=89.6</p>
<p>Thanks Anonymous1993, I was rather squaring 1*10^-8 and I was getting the wrong answer. But I understand it now.</p>
<p>1.Which of the following does not react with dilute solution of H2SO4…
A) NaNO3 B) Na2S C) Na3PO4 D) Na2CO3</p>
<p>Barrons says the answer is A because NaNO3 requires heat to react with H2SO4</p>
<ol>
<li>A student made the following observations in the laboratory.
(a) Sodium metal reacted vigorously with water while a strip of magnesium did not seem to react at all.
(b) The magnesium strip reacted with dilute hydrochloric acid faster than an iron strip
(c) A copper rivet suspended in silver nitrate solution was covered with silver-colored stalactites in several days, and the resulting solution had a blue color
(d) Iron filings dropped into the blue solution were coated with an orange color</li>
</ol>
<p>The order of decreasing strength as reducing agent is
(A) Na, Mg, Fe, Ag, Cu
(B) Mg, Na, Fe, Cu, Ag
(C) Ag, Cu, Fe, Mg, Na
(D) Na, Fe, Mg, Cu, Ag
(E) Na, Mg, Fe, Cu, Ag</p>
<p>The answer for question 2 is E</p>
<p>I noticed the are questions on gases on each practice test I have taken so far. Does anyone have a comprehensive summary on the solubilities and densities( whether they are heavier than air or not) of the common gases. I would be great if anyone could share it with us. I remember we were once taught how to determine whether a gas is denser that air or not, but I do not remember how to go about it. Anyone knows that…(what is the molar mass of air)</p>
<p>Are there generally questions about hybrid orbitals, pi bonds, sigma bonds, etc? Also, do I need to know a lot about organic chemistry (like alkenes or functional groups)?</p>
<ol>
<li>A is correct but not because of heating anything
NaNO3 + H2SO4 -> NaNO3 + H2SO4 will not occur</li>
</ol>
<p>If you look at the net ionic, everything cancels out because all of the products and reactants dissolve in solution.</p>
<ol>
<li><p>You never gave me a choice for E</p></li>
<li><p>You just have to remember that Na is really strong and Cu is really weak.</p></li>
</ol>
<p>You will have to know some of that. You don’t need to study much organic though.</p>
<p>Anonymous1993, why cant the equation be written this way</p>
<p>2NaNO3 + H2SO4 -> Na2(SO4) + 2HNO3</p>
<p>From the equation, nothing shows that the reaction will not occur.</p>
<p>Did you finish AP chemistry already? How are you so good at chemistry? (:</p>
<p>
</p>
<p>Write out the net-ionic
Na^+ + NO3^- + H^+ + SO4^- → Na^++ SO4^- + H^+ + NO3^-
Everything cancels out.</p>
<p>
</p>
<p>Yes.</p>
<p>Anonymous1993,</p>
<p>I have some more questions…I just took the 3rd practice test from PR book and found that it was a lot harder than the previous 2 tests…
Anyway, I have some questions I don’t understand from the book explanations.
43. Identify the molecule/ion with the greatest potential to act as a lewis acid.
When I saw the question, I remembered that Lewis acids are molecules that accept electrons-right? But then I noticed that the - and + signs were on the upper left of the chem formulas of the answer choices…can you please help!
A)^+CH3
B)^-CN
C)NH3
D)BF4^-
E)CO2</p>
<p>Zn(s)|ZnCl2(aq)| |Cl^-(aq)|Cl2(g)|C(s)
50. In the electrochemical cell described by the cell diagram above, what reaction occurs at the anode?
How can you tell which is the anode/cathode? I’m so confused when it comes to these types of questions.</p>
<p>Another major problem I’m having is doing the calculations by hand…things like dividing 5.7g by 143.4g/mol…
Also, I noticed some questions require you to know certain chem reactions in order to do them…which ones do you suggest that I memorize? (like the ones related to reactivity series—which I need to know right? I forgot the categories of it since I haven’t used it that much yet in AP chem.</p>
<p>Also, there was a question asking the color of gases…that I also need to know for the test? Another one that I didn’t know was the color of mixing something that makes a purple solid…so what are the main “color” type things that I should know, and the important chemical reactions (even the basic ones, b/c I forgot a lot of them, and can’t find my chem stuff from last year, so I’m relying on the prep book, which doesn’t have this stuff.) </p>
<p>Also,
When they ask about gibb’s free energy, and ask if a spontaneous reaction will occur/something like that, wouldn’t it always be spontaneous just in opposite directions? So I’m assuming that in those questions they are referring to the fwd direction (which G<0 for a spontaneous rxn, right?)</p>
<p>Thanks a lot!</p>
<p>I am going to answer them in a different order.
50. remember the trick
An Ox----Red Cat (oxidation occurs at the anode; reduction occurs at the cathode)
Oil Rig(Oxidation Is Losing electrons; Reduction Is Gaining electrons)</p>
<p>So: Zn(s) is the anode because it’s positively charged and thus wants to lose electrons?
The right side are all nonmetals and have negative charges, which means they want to gain electrons, which is the cathode right?</p>
<p>I am not sure exactly how to explain reactions to you unless you give me some specific reactions you need help with. For the colors of chemicals, I also do not know how to explain every single one to you. I knew how to do it from lab experience. The big one they ask is permanganate, which is purple.</p>
<p>For free energy, you are correct.</p>