<p>1) anything with a Cl-, Br-, I-, or SO42- anion. e.g. NaCl.
this is so because NaCl is ionic and dissociates completely, so there are Na+ and Cl- ions. the Cl- and the Ag+ will form AgCl precipitate. same with Pb2+ and Cl- to form PbCl2</p>
<p>2) AgCl
it has a smaller Ksp. this means that it favors products more in the reaction:
AgCl <—> Ag+ + Cl-
than PbCl2 does</p>
<p>3) first, you need to find out the Cl- concentration when PbCl2 precipitates, so when [Pb2+][Cl-]^2 = Ksp, Ksp = 1.6 x 10^-5, [Pb2+] = .02 M
[Cl-] = .0283 M</p>
<p>then, you take that value for [Cl-] and plug it into [Ag+][Cl-] = Ksp
so: <a href=“.0283”>Ag+</a> = 1.8 x 10^-10
so: [Ag+] = 6.36 x 10^-9</p>
<p>i think thats right. i would have liked it if a cleaner number came out.
can anybody check this?</p>
<ol>
<li>which of the following has the lowest conductivity?
a) 0.1 M CuSO4
b) 0.1 M KOH
C) 0.1 M BaCl2
d) 0.1 M HF <– ANSWER!
e) 0.1 M HNO3</li>
</ol>
<p>All the others are strong acids/strong bases/soluble salts <– which are all electrolytes aka “electricity conducting” HF only ionizes to a small percentage (weak acid) therefore does not conduct electricity very well</p>
<p>Do you guys think we’ll have to know the Clausius-Clapeyron equation? I came across it in my review today, and this is the first time I’ve ever seen it lol.</p>
<ol>
<li><p>The nonvolatile compound ethylene glycol, C2H6O2, forms nearly ideal solutions with water. What ist he vapor pressure of a solution made from 1.00 mole of C2H6O2 and 9.00 moles of H2O if the vapor pressure of pure water at the same temperature is 25.0 mm Hg?
a. 2.5 mm Hg
b. 7.5 mm Hg
c. 12.5
d. 22.5 —answer
e. 27.5 </p></li>
<li><p>A 360. mg sample of aspirion, C9H8O4, (molar mass 180. g), is dissolved in enough water to produce 200. mL of solution. What is the molarity of aspirin in a 50. mL sample of this solution?
a. 0.08M b. 0.04M c. 0.02M d. 0.01M e. 0.0025M (d is the answer)</p></li>
</ol>
<p>haha, you guys just DEVOURED those problems didnt you xD
congratulations though… :D</p>
<p>want more?
it is suggested that SO2, which contributes to acid rain, could be removed from a stream of waste gases by bubbling the gases through 0.25 molar KOH, thereby producing K2SO3. what is the maximum mass of SO2 that could be removed by 1000 L of the kOH solution?
a) 4 kg
b) 8 kg
c) 16 kg
d) 20 kg
e) 40 kg </p>
<ol>
<li><p>when a 1g sample of limestone was dissolved in acid, 0.38 gram of CO2 was generated. if the rock contained no carbonate other than CaCO3, what is the percent of CaCO3 by mass in the limestone?
a) 17%
b) 51%
c) 64%
d) 86%
e) 100%</p></li>
<li><p>a 1 molar solution of which of the following salts has the highest pH?
a) NaNO3
B) Na2CO3
c) NH4Cl
D) NaHSO4
E) Na2SO4</p></li>
<li><p>what is the maximum mass of copper that could be plated out by electrolyzing aqueous CuCl2 for 16 hours at a constant current of 3 amps? (1 faraday = 96500 coulombs)
a) 28 g
b) 57 g
c) 64 g
d) 114 g
e) 128 g</p></li>
</ol>
<p>"Can someone explain finding rate law from a mechanism?</p>
<p>I know it has to deal with the slow step, but from there I’m lost.</p>
<p>Use this as an example:
Cl2 <-> 2Cl (fast)
Cl + CO <-> COCl (fast)
Cl2 + COCl -> COCl2 + Cl (slow)</p>
<p>The answer is rate = k[CO][Cl2]^(3/2) btw, but please explain"</p>
<p>Rate determining step is the third one. rate=k[CL2][COCl]. However, COCl is an intermediate. k[COCl]=k[Cl][CO], [COCl]=k[Cl][CO], overall rate so far is rate=k[Cl2][Cl][CO]. However, Cl is also an intermediate. k[Cl]^2=k[Cl2], [Cl]=k[Cl2]^1/2. Insert back into first one: rate=k[Cl2][Cl2]^1/2[CO]=k[Cl2]^3/2[CO]</p>
<p>For number two, it’s called Raoult’s Law I think. Basically it’s:</p>
<p>P (change in vapor pressure) = P (vapor pressure of pure solvent) * X (mole fraction)</p>
<p>So in this case: x = (25 * (1/10)) = 2.5. The reason it’s 1/10 is there’s 1 mole ethylene glycol out of the 10 moles of substance in the solution.</p>
<p>So since any solute will decrease the vapor pressure, you subtract the change from the original vapor pressure to get the new vapor pressure of the solution.</p>
<p>25-2.5 = 22.5.</p>
<p>For number 3, all you do is find the molarity.</p>
<p>360 mg = .360 g</p>
<p>.360 g C9H8O4 / (180 g C9H8O4/ 1 mol C9H8O4) = 0.002 mol C9H8O4</p>
<p>0.002 mol C9H8O4/200 mL = 0.01 M C9H8O4</p>
<p>The molarity will not change because the ratio of moles to volume will remain the same despite any change in volume, as the ratio of moles to that volume will also be changed.</p>
<ol>
<li>what is the maximum mass of copper that could be plated out by electrolyzing aqueous CuCl2 for 16 hours at a constant current of 3 amps? (1 faraday = 96500 coulombs)
a) 28 g
b) 57 g
c) 64 g
d) 114 g
e) 128 g</li>
</ol>
<p>wait sorry, for number3, why wont the molarity change. I still don’t quite understand it. I just basically did .002 divided by the new volume of .05…but that’s wrong…</p>
<p>Here’s more for others too thanks again</p>
<ol>
<li><p>The pH of a solution prepared by the addition of 10. mL of 0.002 M KOH (aq) to 10. mL of distilled water is closest to…
A. 12 b. 11 c.10 d.4 e.3 (answer is b) </p></li>
<li><p>When mixed each of the following pairs of reactants gives visible evidence of a chemical reaction except:
a. Na2CO3 (s) and HCl (aq)
b. Zn (s) and HCl (aq)
c. Ba(NO3)2 (aq) and Na2SO4 (aq)
d. FeCl3 (aq) and KOH (aq)
e. NH4Cl (aq) and HCl (aq)</p></li>
</ol>
<p>Is NH4Cl an acid because it breaks down into H+ and NH3?</p>
<ol>
<li>An electric current of 1.00 ampere is passed thru an aqueous solution of Ni(NO3)2. How long will it take to plate out exaactly 1.00 mol of nickel metal, assuming 100 percent current efficiency? (1 faraday= 96,500 coulombs = 6.02 x 10^23electrons)
a. 386000sec b. 193000 sec c. 96500 sec d. 48200sec e. 24100 sec</li>
</ol>
thanks again</p>