<p>Calculate the pH of the solution resulting from the adition of 20.0 mL of .100 M NaOH to 30.0 mL of 0.100 M HNO3.
a. 1.35
b. 1.7 (my answer)
c. 1.95
d. 2.52
e. 2.8</p>
<p>Calculate the pH of a solution prepared by mixing 300 mL of 0.10 M HF and 200 mL of 0.10 M KOH. (i have no idea how to do this one)
a. 2.82
b. 2.96
c. 3.32
d. 3.44
e. 3.53</p>
<p>i thought it would be just:
K2O + H2O –> 2KOH (and since KOH is a strong base –> K+ + OH-)</p>
<p>i would do separate ice boxes for HF and KOH (do you get Ka for HF?) you couldn’t get that on an MC though since you have no calculator</p>
<p>on the equation part (#4), is it better to put the phase and get it wrong than to not put it? I heard they don’t count it either way…is this so?</p>
<p>k thanks everybody! I was actually studying an old test from class. does anybody have their 2008 exam with them because I just have a few graph questions that I cant really type here…:]
arghg i 'm just mad that I 'm cramming so much right now…I should’ve started studying earlier. …</p>
<p>Can someone quickly go over Ka and Kb? For some reason everything I’ve been looking at goes straight into it and doesn’t explain what you put where.</p>
<p>ka and kb = dissociation constant for weak acid and base respectively</p>
<p>standard equilibrium, that is, if all letters used are not liquids/solids as they do not count in the equilibrium expression</p>
<p>aA + bB <–> cC + dD</p>
<p>(C^c)(D^d) = K
------------
(A^a)(b^B)</p>
<p>Ka = dissociation constant for weak acid</p>
<p>HA <–> H+ + A-</p>
<p>[H+][A-] =Ka
---------
[HA]</p>
<p>Kb= dissociation constant for weak base</p>
<p>B + H20 <—> BH+ + OH-</p>
<p>[BH+][OH-] =Kb
------------
**</p>
<p>Notes: Ka * Kb = Kw = 1^-14</p>
<p>Hope this helped</p>
<p>for Ka, say you have the dissociation of a weak acid, lets say HF.
the reaction is:</p>
<p>HF <—> H+ + F-</p>
<p>however, not all of the HF is going to ionize completely. it will actually tend to stay more in its HF form, since it is a weak acid.</p>
<p>for any equilibrium constant expression, it is the concentration of the products raised to each of their coefficients multiplied by each other all divided by the concentration of the reactants.</p>
<p>so for this reaction, Ka, since it is an acid, would be:</p>
<p>Ka = ([H+][F-])/[HF]
i think</p>
<p>Can someone answer this question?</p>
<ol>
<li>Which of the following salts will produce a colorless solution when added to water?</li>
</ol>
<p>A. Cu(NO3)2
B. NiCl2
C. KMnO4
D. ZnSO4
E. FeCl3</p>
<p>Any predictions for the free response: thermo, kinetics, electrochem, bonding, etc.? Also does anyone think titration might be on the free response? There hasn’t been a titration problem since, what, 2003?</p>
<p>So you are essentially putting the products over the reactants and excluding solids and liquids, correct (or putting what is dissociated on the top and the reactant on the bottom)? From that you would most likely plug in the given values.</p>
<p>im pretty sure ZnSO4 makes a colorless solution</p>
<p>Cu(NO3)2 makes blue
NiCl2 makes green (?)
KMnO4 makes purple
ZnSO4 colorless
FeCl3 makes either yellow, green, or red, i dont remember</p>
<p>to test if it’s polar find the difference in electronegativites of the elements. Also check the VSEPR shape to make sure it has a net dipole moment. The molecules with the greatest london dispersion forces will also have the greatest molar masses because the electron cloud is more polarizable.</p>
<p>^^ right.</p>
<p>What’s the typical curve for chem? Like how many missed on MC/FRQ? I’m sure this has already been answered, but I can’t find it.</p>
<p>@CSB111</p>
<p>yes, basically.</p>
<p>You might want to learn RICE tables if you haven’t already. It’s very common and most likely 90% chance that you will need to use this for the equilibrium problem</p>
<p>somebody already answered my question but I was just kind of confused on the steps that person took. sorry but can anybody answer this question again? lol. thanks.</p>
<p>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 exactly 1.00 mol of nickel metal, assuming 100 percent current efficiency? (1 faraday = 96500 coulombs= 6.02 x 10^23 electron)</p>
<p>The nonvolatile compound ethylene glycol, C2H6O2, forms nearly ideal solutions with water. What is the vapor pressure of a soution 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? </p>
<p>How many electrons are transferred in the reaction represented by the balanced equation below?
2MnO4-(aq) + 10Br-(aq) + 16H+(aq) yields 2Mn2+ (aq) + 5Br2(aq) + 8 H2O (l)</p>
<p>someone should go over some organic chem, or is that not super important to learn?</p>
<ol>
<li>Which of the following salts will produce a colorless solution when added to water?</li>
</ol>
<p>A. Cu(NO3)2 (Blue)
B. NiCl2 (Green)
C. KMnO4 (Purple)
D. ZnSO4 (Colorless)
E. FeCl3 (Orange-y)</p>
<p>@manbean</p>
<p>I saw those RICE tables in the Barrons book. If I remember correctly, isn’t it x^2 on the top over the molarity they give?</p>
<p>but why is it colorless? haha I’m like using every concept I remember and can’t reason to why it is what it is</p>
<p>^ it just is. Don’t fight the system = D.</p>